Test for glucose tolerance, sugar curve: analysis and rate, how to pass, the results

The upper limit of the norm for glucose tolerant dough is 6.7 mmol / l, the lower take the initial value of sugar, a clear lower limit of the norm for the study does not exist.

With a decrease in the load test, we are talking about all sorts of pathological conditions, they entail a violation of carbohydrate metabolism, glucose resistance. With latent diabetes mellitus of the second type, symptoms are observed only upon the occurrence of adverse conditions (stress, intoxication, trauma, poisoning).

If metabolic syndrome develops, it entails dangerous health problems that can cause the patient to die. Such diseases include myocardial infarction, arterial hypertension, coronary insufficiency.

Other violations will be:

  • excessive thyroid, pituitary,
  • all sorts of disorders of regulatory activity,
  • suffering central nervous system
  • gestational diabetes,
  • inflammation in the pancreas (acute, chronic).

The oral glucose tolerance test is not a routine study, however, everyone should know their sugar curve to determine the dreaded complications.

The analysis must be done with confirmed diabetes mellitus.

Who should be under special control

Sugar


A glucose tolerance test is primarily indicated for patients who are at risk of type 2 diabetes. No less important is the analysis in pathological conditions that are of a permanent or periodic nature, leading to impaired carbohydrate metabolism and the development of diabetes.

In the area of ​​attention are people who have blood relatives already have diabetes, are overweight, hypertension and lipid metabolism. The endocrinologist will prescribe an analysis with glucose for atherosclerotic vascular disease, gouty arthritis, hyperuricemia, a long-term pathology of the kidneys, blood vessels, heart and liver.

In the risk group there is also an episodic increase in glycemia, traces of sugar in the urine, patients with obstetric history, aged 45 years, with chronic infections, neuropathy of unknown etiology.

In the cases considered, the tolerance test should be carried out even if the fasting glucose indicators are within the normal range.

What can affect the results


If a person suspected a violation of glucose resistance, insulin cannot neutralize a surplus of sugar, it needs to know that various factors can affect the test result. Problems with glucose tolerance are sometimes diagnosed in people without diabetes.

The reason for the decrease in tolerance will be the habit of frequently eating sweets and confectionery, sweet carbonated drinks. Despite the active work of the insular apparatus, the level of glucose in the blood increases, its resistance to it decreases. Intense physical exertion, drinking alcohol, smoking strong cigarettes, psychoemotional loads on the eve of the study can also reduce glucose resistance.

In the course of evolution, pregnant women have developed a protective mechanism against hypoglycemia, but doctors are sure that it bears more harm than good.

Glucose resistance is also associated with overweight, many diabetics are obese. If a person thinks about his health and goes on a low-carb diet:

  1. he will get a beautiful body
  2. improve well-being
  3. will reduce the likelihood of developing diabetes.

Diseases of the organs of the gastrointestinal tract, for example, impaired absorption, motility, affect the tolerance test scores.

These factors, although they are physiological manifestations, should make a person think about his health.

Changing the results to the bad side should make the patient to reconsider eating habits, learn to control their emotions.

The role of glucose in humans

How to get glucose in the body? To do this, it is enough to eat sweets, most fruits and vegetables, granulated sugar or honey, as well as foods that contain starch.

During pregnancy, it is important to regularly monitor your glucose levels.

To maintain the correct level of substances in the body requires the hormone insulin, which provides the necessary balance. Increasing or decreasing this level means having a serious illness, such as diabetes, which is formed when there is an insulin deficiency.

Eating sweets or honey helps to increase the concentration of sugar in the bloodstream. This serves as a signal for the body to begin active insulin production for the cells to absorb the elements and energy they have received, as well as to reduce the glucose concentration.

In addition, the hormone insulin provokes the accumulation of glucose by the body in reserve for its excessive intake.

The level of glucose is of particular importance when carrying a child. Since the imbalance of this component causes the development of ailments in a pregnant woman, it has a negative effect on the development of the fetus.

To determine the concentration of glucose in the blood using a special apparatus called a blood glucose meter. It can be purchased independently at a pharmacy, the average price for a device is 700-1000 rubles. Additionally, you will need to purchase special test strips, their price is influenced by the amount in the package and the manufacturer. The average cost of test strips is 1200-1300 rubles for 50 pieces.

How to test for glucose during pregnancy

In order for glucose indicators to be reliable, it is necessary to properly prepare for the analysis. It is advisable a few days before the procedure to reduce the amount or completely eliminate from the diet sweets and pastries, fruits and vegetables that contain a lot of starch. You should also forget about alcoholic beverages (do you remember that they are not recommended to drink during pregnancy ?!).

The analysis is given on an empty stomach, the last meal should be no later than 8 pm. It is allowed to drink ordinary clean water without gases. In the morning it is not recommended to brush your teeth and chew the chewing gum, as they can distort the results of the analysis.

For the study can use both venous blood and capillary (from the finger).

Diabetes - the epidemic of the XXI century

The rapid increase in the incidence of this pathology has caused an urgent need to develop new standards in the treatment and diagnosis of diabetes. The World Health Organization developed the text of the UN Resolution in 2006. This document contained recommendations to all Member States “to develop national strategies for the prevention and treatment of this pathology”.

The most dangerous consequences of the globalization of the epidemic of this pathology is the mass of systemic vascular complications. In the majority of patients, nephropathy and retinopathy develop on the background of diabetes mellitus, the great vessels of the heart, brain, peripheral vessels of the legs are affected. All these complications lead to the disability of patients in eight cases out of ten, and in two of them - to death.

In this regard, the FSBI "Endocrinological Research Center of the Russian Academy of Medical Sciences" under the Ministry of Health of Russia have improved the "Algorithms of specialized medical care for patients suffering from hyperglycemia." According to the results of the control-epidemiological studies conducted by this organization from 2002 to 2010, one can speak of the excess of the true number of patients suffering from this disease over the number of officially registered patients four times. Thus, diabetes in Russia is confirmed in every fourteenth inhabitant.

The new edition of “Algorithms” focuses on a personalized approach to determining the therapeutic goals of controlling carbohydrate metabolism and blood pressure indicators. The positions concerning the treatment of vascular complications of pathology were also revised, new provisions were made on the diagnosis of diabetes, including during the gestational period.

Principle of laboratory test

As you know, insulin is a hormone that converts the glucose that has entered the bloodstream and transports it to every cell in the body in accordance with the energy needs of various internal organs. With insufficient insulin secretion, we are talking about type 1 diabetes. If this hormone is produced in sufficient quantity, but its susceptibility to glucose is disturbed, diabetes of the second type is diagnosed. In both cases, the delivery of the glucose tolerant test will determine the degree of overestimation of the values ​​of sugar in the blood.

Indications for analysis

Today, such a laboratory test can be taken in any medical institution due to the simplicity and general availability of the method. If suspected glucose susceptibility is suspected, the patient receives a referral from a doctor and goes to the glucose tolerance test. Wherever this study is conducted, in a budget or private clinic, specialists use a unified approach in the process of laboratory examination of blood samples.

The sugar tolerance test is most often prescribed to confirm or exclude prediabetes. For the diagnosis of diabetes mellitus, there is usually no need for a stress test. As a rule, it is sufficiently recorded in laboratory conditions that exceeds the indicator of glucose in the bloodstream.

Often there are situations in which the blood sugar level remains in the normal range on an empty stomach, so the patient, having passed the usual blood sugar tests, always received satisfactory results. The glucose tolerant test, in contrast to the usual laboratory diagnosis, allows to determine the violations to the insulin susceptibility to sugar exactly after saturation of the body. If the concentration of glucose in the blood significantly exceeds the norm, but the analyzes performed on an empty stomach do not indicate pathology, prediabetes is confirmed.

The reasons for the PGTT doctors believe the following circumstances:

  • the presence of symptoms of diabetes mellitus at normal laboratory values, that is, the diagnosis was not previously confirmed,
  • genetic predisposition (in most cases, diabetes is inherited by a child from mother, father, grandparents),
  • excess of the sugar content in the body before eating, but there are no specific symptoms of the disease,
  • glucosuria - the presence of glucose in the urine, which should not be in a healthy person,
  • obesity and overweight.

In other situations, it may also be decided to conduct a glucose tolerance test. What else could be indications for this analysis? First of all pregnancy. The study is performed in the second trimester, regardless of whether the fasting blood glucose rate is too high or within the normal range - all expectant mothers without exception pass the glucose susceptibility test.

Glucose Tolerance in Children

At an early age, patients who have a predisposition to the disease are referred to the study. Periodically, the analysis will have to a child who was born with a large weight (more than 4 kg) and as he grows up also has excess body weight. Infections of the skin and poor healing of minor abrasions, wounds, scratches - all this is also the basis for clarifying the level of glucose. There are a number of contraindications for the glucose tolerant test, which will be discussed later, therefore such an analysis is not done without special need.

How is the procedure itself

This laboratory analysis is performed exclusively in stationary conditions under the supervision of medical staff. Here is how the glucose tolerance test is conducted:

  • In the morning, strictly on an empty stomach, the patient gives blood from a vein. Urgently determined by the concentration of sugar in it. If it does not exceed the norm, proceed to the next stage.
  • The patient is given a sweet syrup, which he should drink. It is prepared as follows: 75 g of sugar are added to 300 ml of water. For children, the amount of glucose in the solution is determined on the basis of 1.75 g per 1 kg of weight.
  • A couple of hours after the syrup is injected, venous blood is collected again.
  • The dynamics of changes in the level of glycemia is evaluated and the results of the test are given.

To avoid errors and inaccuracies, the sugar level is determined immediately after blood sampling. Prolonged transportation or freezing is not allowed.

Deciphering Sample Results

The obtained results are evaluated in comparison with normal indices, which are confirmed in healthy people. If the data obtained exceeds the established range, the experts make the appropriate diagnosis.

For morning blood sampling taken from a patient on an empty stomach, the norm is a value of less than 6.1 mmol / l. If the indicator does not go beyond 6,1-7,0 mmol / l, they speak about prediabetes. In the case of obtaining results exceeding 7 mmol / l, there is no doubt that a person has diabetes. The second part of the test is not carried out due to the risk described above.

A couple of hours after taking the sweet solution, blood is taken from the vein again. This time, a value not exceeding 7.8 mmol / l will be considered the norm. A result of more than 11.1 mmol / l is indisputable evidence of diabetes, and prediabetes is diagnosed at a value between 7.8 and 11.1 mmol / l.

The oral glucose tolerance test is a comprehensive laboratory analysis that records the pancreatic response to the administration of a significant amount of glucose. The results of the analysis can indicate not only diabetes mellitus, but also other diseases of different body systems. After all, a violation of glucose tolerance is not only inflated, but also underestimated.

If blood sugar is below normal values, this is called hypoglycemia. If it is present, the doctor may make an assumption about such diseases as pancreatitis, hypothyroidism, and liver pathologies. Glucose in the blood below the norm can be the result of alcohol, food or drug poisoning, the use of arsenic. Sometimes hypoglycemia is accompanied by iron deficiency anemia. In any case, at low values ​​of the glucose tolerance test, we can talk about the need to undergo additional diagnostic procedures.

In addition to diabetes mellitus and pre-diabetes, an increase in glycemia may indicate disturbances in the endocrine system, liver cirrhosis, kidney diseases, and the vascular system.

Biochemical diagnosis of carbohydrate metabolism disorders

The glucose tolerance test is required to track blood sugar levels. It is carried out with little effort using a minimum of funds. This analysis is important for diabetics, healthy people and future mothers in the later periods.

Impaired glucose tolerance, if necessary, can be found out even at home. The study is conducted both among adults and in children from 14 years. Compliance with the necessary rules allows you to make it more accurate.

There are two types of GTT:

There are different ways to analyze the method of introducing carbohydrates. The oral glucose tolerance test is considered a simple research method. You just need to drink sweetened water a couple of minutes after the first blood collection.

The second method for glucose tolerance is performed by injecting the solution intravenously. This method is used when the patient is unable to drink the sweet solution by herself. For example, the test for glucose tolerance intravenously is indicated for severe toxemia of pregnant women.

The blood test results are assessed two hours after the sugar enters the body. The starting point is the time of the first blood collection.

The glucose tolerance test is based on studying the response of the insular apparatus to its entry into the blood. Biochemistry of carbohydrate metabolism has its own characteristics. In order for glucose to be assimilated normally, you need insulin to regulate its level. Insufficiency of the insular apparatus causes hyperglycemia - an excess of the monosaccharide standard in serum.

Simple and reliable test

In other, quite often, cases (insufficiency of the insular apparatus, increased activity of the contra-insulin hormones, etc.), the level of glucose in the blood can increase significantly and lead to a condition called hyperhycemia. The degree and dynamics of the development of hyperglycemic conditions can be influenced by many agents, however, the fact that insulin deficiency is the main cause of an unacceptable increase in sugar in the blood has long been beyond doubt - that is why the glucose tolerant test, the “sugar curve”, GTT or glucose tolerance test is widely used in the laboratory diagnosis of diabetes. Although GTT is used and helps in the diagnosis of other diseases too.

The most convenient and common sample for glucose tolerance is considered a single load of carbohydrates taken orally. The calculation is as follows:

  • 75 g of glucose, diluted with a glass of warm water, is given to a person not burdened with extra pounds,
  • People who have a large body weight, and women who are in a state of pregnancy, increase the dose to 100 g (but no more!)
  • Children try not to overload, so the number is calculated strictly in accordance with their weight (1.75 g / kg).

In 2 hours after glucose is drunk, they control the sugar level, taking the result of the analysis obtained before the load (on an empty stomach) as the initial parameter. The norm of blood sugar after ingestion of such a sweet "syrup" should not exceed the level 6.7 mmol / l, although in some sources a lower index may be indicated, for example, 6.1 mmol / l, therefore, when deciphering the analyzes, one should focus on the specific laboratory conducting the testing.

If in 2-2.5 hours the sugar content rises to 7.8 mol / l, then this value already gives grounds to register a violation of glucose tolerance. Indicators above 11.0 mmol / l - disappoint: glucose to its norm is not particularly in a hurry, continuing to remain at high values, which makes you think about a poor diagnosis (DM), which provides the patient with NOT a sweet life - with a glucosimeter, diet, pills and regular visit the endocrinologist.

And here is how the change in the data of diagnostic criteria looks in the table depending on the state of carbohydrate metabolism of certain groups of people:

Analysis resultBlood glucose (from finger) on an empty stomach, mmol / lSugar in capillary blood 2 hours after taking glucose, mmol / l
Healthy peopleup to 5.5 (up to 6.1 depending on the method)less than 6.7 (some methods less than 7.8)
If you suspect a violation of glucose toleranceabove 6.1 but below 6.7more than 6.7 (or in other laboratories - more than 7.8), but less than 11.0
Diagnosis: diabetesabove 6.7more than 11.1

Meanwhile, using a single determination of the results in violation of carbohydrate metabolism, you can skip the peak of the "sugar curve" or not wait for it to decrease to the initial level. Concerning The most reliable methods include measuring the concentration of sugar 5 times within 3 hours. (1, 1.5, 2, 2.5, 3 hours after taking glucose) or 4 times every 30 minutes (last measurement after 2 hours).

We will return to the question of how the analysis is done; however, modern people are no longer satisfied with simply stating the essence of the research. They want to know what is happening, what factors can affect the final result and what needs to be done so as not to be registered with an endocrinologist, as patients who regularly write out free prescriptions for drugs used for diabetes.

Norm and deviations of glucose tolerance test

The norm of the glucose-loading test has an upper limit of 6.7 mmol / l, the initial value of the index to which the glucose present in the blood strives is taken as the lower limit. in healthy people, it quickly returns to the initial result, and in diabetics it “gets stuck” at high numbers. In this regard, the lower limit of the norm, in general, does not exist.

A decrease in the glucose-loading test (meaning that glucose does not have the ability to return to its original digital position) may indicate various pathological conditions of the body, leading to impaired carbohydrate metabolism and a decrease in glucose tolerance:

  1. Latent diabetes mellitus type II, which does not manifest symptoms of the disease in a normal environment, but reminds of problems in the body under adverse circumstances (stress, trauma, poisoning and intoxication),
  2. The development of metabolic syndrome (insulin resistance syndrome), which, in turn, entails a rather severe pathology of the cardiovascular system (arterial hypertension, coronary insufficiency, myocardial infarction), often leading to untimely death of a person,
  3. Excessive activity of the thyroid gland and the anterior pituitary gland,
  4. Suffering of the central nervous system,
  5. The disorder of regulatory activity (the predominance of the activity of one of the departments) of the autonomic nervous system,
  6. Gestational diabetes (during pregnancy)
  7. Inflammatory processes (acute and chronic), localized in the pancreas.


It should be noted that, although GTT is not referred to as routine laboratory tests, each person, nevertheless, should keep in mind the “sugar curve”, so that at certain age and under certain circumstances not to miss the development of such terrible diseases as diabetes mellitus and metabolic syndrome. And all the more you need to remember about the timely test for glucose tolerance, since prerequisites have already become apparent, and the person added to the risk group.

Who threatens to get under special control

The glucose tolerance test is primarily required for people at risk (the development of type II diabetes). Some pathological conditions that are periodic or permanent, but in most cases lead to disruption of carbohydrate metabolism and the development of diabetes, are in the zone of special attention:

  • Cases of diabetes in the family (diabetes in blood relatives),
  • Overweight (BMI - body mass index of more than 27 kg / m 2),
  • Burdened obstetric history (spontaneous abortion, stillbirth, large fetus) or gestational diabetes during pregnancy,
  • Arterial hypertension (blood pressure above 140/90 mm. Hg. Art.)
  • Violation of fat metabolism (laboratory parameters of the lipid spectrum),
  • Vascular disease by the atherosclerotic process,
  • Hyperuricemia (increased uric acid in the blood) and gout,
  • An episodic increase in blood sugar and urine (with psycho-emotional stress, surgery, another pathology) or a periodic unreasonable decrease in its level,
  • Long-term chronic course of diseases of the kidneys, liver, heart and blood vessels,
  • Manifestations of metabolic syndrome (various options - obesity, hypertension, lipid metabolism, blood clots),
  • Chronic infections
  • Neuropathy of unknown origin,
  • The use of diabethogenic drugs (diuretics, hormones, etc.),
  • Age after 45 years.

The test for glucose tolerance in these cases it is advisable to carry out, even if the concentration of sugar in the blood taken on an empty stomach does not exceed normal values.

What affects the results of GTT

A person who is suspected of impaired glucose tolerance should know that many factors can influence the results of the “sugar curve”, even if in fact diabetes does not yet threaten:

  1. If you indulge yourself daily with flour, cakes, sweets, ice cream and other sweet delicacies, the glucose entering the body will not have time to be utilized without looking at the intensive work of the insular apparatus, that is, a special love of sweet foods may result in a decrease in glucose tolerance,
  2. Intense muscular load (training for athletes or heavy physical labor), which is not canceled the day before and on the day of the analysis, can lead to impaired glucose tolerance and distortion of results,
  3. Lovers tobacco smoke risk being nervous due to the fact that a “perspective” of carbohydrate metabolism will emerge if there is not enough time before to give up the bad habit. This is especially true of those who smoke a couple of cigarettes before the examination, and then rush headlong into the laboratory, thereby causing double harm (before taking blood, you need to sit for half an hour, catch your breath and calm down, because psycho-emotional stress also leads to a distortion of the results)
  4. During pregnancy the protective mechanism of hypoglycemia developed during the evolution is includedwhich, according to experts, brings more harm to the fetus than the hyperglycemic state. In this regard, glucose tolerance can naturally be somewhat reduced. For “bad” results (reduction Sahara in the blood) it is also possible to accept a physiological change in carbohydrate metabolism, which is due to the fact that hormones of the child’s pancreas that has started to function are included in the work,
  5. Excess weight - a sign is not at all health, obese are at risk for a number of diseases where diabetes, if it does not open the list, is not in the last place. Meanwhile, a change in the test scores for the better can be obtained from people burdened with extra pounds, but not yet suffering from diabetes. By the way, patients, who in time recollected themselves and went on a rigid diet, became not only slim and beautiful, but also dropped out of the number of potential endocrinologist patients (the main thing is not to break down and adhere to the correct diet)
  6. Glucose tolerance test scores can significantly affect gastrointestinal problems (dysmotility and / or suction).

These factors, which, although they relate (to varying degrees) to physiological manifestations, can make you pretty worried (and, most likely, not in vain). Changing the results can not always be ignored, because the desire for a healthy lifestyle is incompatible with bad habits, or with excess weight, or lack of control over their emotions.

The organism can endure the long-term effect of a negative factor for a long time, but at some stage it can give up. And then a violation of carbohydrate metabolism can become not imaginary, but real, and the test for glucose tolerance can testify to this. After all, even such a very physiological condition, such as pregnancy, but proceeding with impaired glucose tolerance, may ultimately result in a definite diagnosis (diabetes mellitus).

How to take a glucose tolerance test to get the right results.

To get reliable results of the glucose-loading test, the person on the eve of the trip to the laboratory should follow some simple tips:

  • 3 days prior to the study, it is undesirable to significantly change something in your lifestyle (normal work and rest, usual physical activity without undue diligence), but the diet should be somewhat controlled and stick to the amount of carbohydrates recommended by the doctor per day (≈ 125 -150 g) ,
  • The last meal before the study should be completed no later than 10 hours,
  • No cigarettes, coffee and alcohol-containing drinks should last at least half a day (12 hours),
  • You can not load yourself with excessive physical activity (sport and other recreational activities should be postponed for a day or two),
  • It is necessary to skip on the eve of taking individual medication (diuretics, hormones, neuroleptics, adrenaline, caffeine),
  • If the day of the analysis coincides with the monthly in women, the study should be postponed to another time,
  • The test may show incorrect results if the blood was donated during strong emotional experiences, after surgery, at the height of the inflammatory process, with liver cirrhosis (alcoholic), inflammatory lesions of the hepatic parenchyma and diseases of the gastrointestinal tract that occur with glucose absorption disorders.
  • Incorrect digital GTT values ​​may occur with a decrease in potassium in the blood, a violation of the functional abilities of the liver and some endocrine pathology,
  • 30 minutes before the blood sampling (taken from the finger), the person arriving for the examination should sit quietly in a comfortable position and think of something good.

In some (doubtful) cases, the glucose load is carried out by administering it intravenously, when you should do just that - the doctor decides.

How is the analysis carried out

The first analysis is taken on an empty stomach (its results are taken as the starting position), then the glucose is given to drink, the amount of which will be assigned according to the patient’s condition (childhood, obese person, pregnancy).

In some people, a sugary sweet syrup taken on an empty stomach may cause a feeling of nausea. To avoid this, it is advisable to add a small amount of citric acid, which will prevent unpleasant sensations. For the same purpose in modern clinics can offer flavored version of the glucose cocktail.

After the “drink” received, the person being surveyed is sent to “walk” not far from the laboratory. When to arrive at the next analysis, health workers will say, it will depend on the intervals and the frequency with which the study will take place (in half an hour, an hour or two? 5 times, 4, 2 or even once?). It is clear that lying patients “sugar curve” is done in the department (the laboratory assistant comes by himself).

Meanwhile, individual patients are so inquisitive that they are trying to conduct research on their own, without leaving home. Well, imitation of THG to some extent can be considered an analysis of sugar at home (measuring on an empty stomach with a glucometer, breakfast, corresponding to 100 grams of carbohydrates, control of elevation and decrease in glucose). Of course, it is better for the patient not to count any coefficients adopted for the interpretation of glycemic curves. He simply knows the values ​​of the expected result, compares it with the obtained value, writes it down in order not to forget, and later reports them to the doctor in order to present the clinical picture of the course of the disease in more detail.

In laboratory conditions, the glycemic curve obtained after a blood test for a certain time and reflecting a graphic image of the behavior of glucose (rise and fall), calculate hyperglycemic and other factors.

The Baudouin coefficient (K = B / A) is calculated based on the numerical value of the highest glucose level (peak) during the study time (B - max, numerator) to the initial blood sugar concentration (Aish, fasting denominator). Normally, this indicator is in the range of 1.3 - 1.5.

The Rafaleski coefficient, which is called postglycemic, is the ratio of the glucose concentration value 2 hours after a person drank a liquid saturated with carbohydrates (numerator) to the numerical expression of fasting sugar level (denominator). For persons who do not know problems with carbohydrate metabolism, this indicator does not go beyond the limits of the established norm (0.9 - 1.04).

Of course, the patient himself, if he really wants, can also practice, draw something, calculate and assume, however, he must keep in mind that in the laboratory, other (biochemical) methods are used to measure the concentration of carbohydrates in time and plot the graph. . The blood glucose meter used by diabetics is intended for rapid analysis, therefore calculations based on its indications may be erroneous and only confusing.

Causes and symptoms

When a failure of carbohydrate metabolism occurs, there is a violation of glucose tolerance. What it is? NTG is accompanied by an increase in blood sugar above the norm, however, not exceeding the diabetic threshold. These terms are among the main criteria for diagnosing metabolic disorders, including those with type 2 diabetes.


It is noteworthy that today, IGT can be found even in a child. This is due to the acute problem of society - obesity, which causes serious harm to the children's body. If earlier diabetes at a young age arose because of heredity, now this disease is increasingly becoming the result of a poor lifestyle.

It is believed that various factors can provoke such a state. These include genetic predisposition, insulin resistance, problems in the pancreas, some diseases, obesity, lack of exercise.

The characteristic of the violation is asymptomatic. Alarming signs appear in diabetes mellitus type 1 and 2. As a result, the patient is late in treatment, unaware of health problems.

Sometimes, as IGT develops, symptoms characteristic of diabetes appear: severe thirst, a feeling of dry mouth, heavy drinking, and frequent urination. However, such signs do not act as a one hundred percent basis for confirming the diagnosis.

What do these figures mean?

Conducting an oral glucose tolerance test, one feature should be considered. Blood from a vein in a normal state of affairs contains a slightly larger amount of monosaccharide than capillary blood taken from a finger.

Deciphering an oral blood test for glucose tolerance is assessed by the following items:

  • The normal value of GTT - the content of glucose in the blood 2 hours after the injection of the sweet solution does not exceed 6.1 mmol / l (7.8 mmol / l during the collection of venous blood).
  • Impaired tolerance is an indicator higher than 7.8 mmol / l, but less than 11 mmol / l.
  • Pre-diagnosed diabetes mellitus - high rates, namely more than 11 mmol / l.

A single estimated sample has a drawback - you can skip the decline in the sugar curve. Therefore, more reliable data are obtained by measuring the sugar content 5 times in 3 hours or 4 times every half hour. The diabetic curve, the norm of which should not exceed 6.7 mmol / l at the peak, in diabetics freezes at high numbers. At the same time there is a flat sugar curve. While in healthy people a low rate is quickly detected.

Indications and contraindications for GTT

Indications for the test:

  • The body mass index is 30 kg / m2 or exceeds this indicator,
  • the birth of a large (weighing more than 4 kg) child in previous pregnancies,
  • high pressure,
  • heart pathology,
  • a stillbirth in history
  • diabetes mellitus someone
  • gestational diabetes in the past
  • myoma, polycystic ovary or endometriosis before pregnancy.

At the same time GTT is not recommended in the following cases:

  1. In case of toxicosis (more on toxicosis during pregnancy >>>),
  2. after stomach surgery due to a suction disorder,
  3. with ulcers and chronic inflammation of the digestive tract,
  4. in acute infectious or inflammatory process in the body,
  5. with some endocrine diseases,
  6. when taking medications that change the level of glucose.

Methods of testing blood and its components

We will immediately say that it is necessary to reconcile the testimony, taking into account what kind of blood was analyzed during the test.

Can be considered as a whole capillary blood, and venous. However, the results do not differ so much. So for example, if we look at the result of the whole blood analysis, they will be somewhat less than those obtained during the testing of blood components obtained from a vein (plasma).

With whole blood, everything is clear: they pricked a finger with a needle, took a drop of blood for biochemical analysis. For these purposes, blood does not require much.

The venous system is somewhat different: the first blood sample from a vein is placed in a cold tube (it is better, of course, to use a vacuum tube, then extra frauds with blood preservation will not be needed), which contains special preservatives that allow you to save the sample until the test itself. This is a very important stage, since excess components should not be mixed with blood.

Preservatives usually use several:

  • sodium fluoride at the rate of 6mg / ml whole blood

It slows down the enzymatic processes in the blood, and at such a dosage it practically stops them. Why is this necessary? First, it is not for nothing that blood is placed in a cold tube. If you have already read our article on glycated hemoglobin, then you are aware that hemoglobin is “sugared” under the effect of heat, provided that there is a large amount of sugar in the blood for a long time.

Moreover, under the action of heat and with the actual access of oxygen, the blood begins to "deteriorate" faster. It oxidizes, becomes more toxic. To prevent this from occurring, in addition to sodium fluoride, one more ingredient is added to the tube.

It prevents blood from clotting.


Then the tube is placed in ice, and special equipment is prepared for the separation of blood into components. Plasma is needed to get it using a centrifuge and, sorry for the tautology, centrifuged the blood. Plasma is placed in another tube and direct analysis is already beginning.

All these frauds must be carried out quickly and within a thirty-minute interval. If the plasma is separated later than this time, then the test can be considered failed.

Further, with regard to the further process of analysis of both capillary and venous blood. In the laboratory can use different approaches:

  • glucose oxidase method (norm 3.1 - 5.2 mmol / liter),

To put it very simply and roughly, it is based on enzymatic oxidation with glucose oxidase, when hydrogen peroxide is formed at the output. The previously colorless orthotolidine, under the action of peroxidase, acquires a bluish tint. About the concentration of glucose "says" the amount of pigmented (painted) particles. The more of them - the higher the level of glucose.

  • orthotoluidine method (norm 3.3 - 5.5 mmol / liter)

If in the first case there is an oxidative process based on an enzymatic reaction, then here the action takes place in an already acidic medium and the intensity of staining occurs under the action of an aromatic substance derived from ammonia (this is orthotoluidine). A specific organic reaction occurs, as a result of which glucose aldehydes are oxidized. The amount of glucose is indicated by the color saturation of the “substance” of the solution obtained.

The orthotoluidine method is considered to be more accurate; accordingly, it is more often used in the process of blood analysis at GTT.

In general, there are a lot of methods for determining glycemia, which are used for tests, and all of them are divided into several large categories: colorimetric (second method, examined by us), enzymatic (first method, examined by us), reductometric, electrochemical, test strips (used in blood glucose meters). and other portable analyzers), mixed.

Venous blood 2 hours after carbohydrate loading

diagnosismmol / liter
norm The test for glucose tolerance during pregnancy - a justified need or unnecessary examination

The appointment of this type of research to a future mother causes a negative reaction in many women and this is quite understandable. The procedure often causes discomfort in the form of nausea, dizziness. In addition, the glucon loading test is carried out in the morning, for several hours (about 3). At this time (as well as the day before in preparation for the study) it is necessary to exclude the consumption of any kind of food, which is often also a certain difficulty for a “pregnant” organism. It is for these reasons that many women "in position" refuse to conduct research.
How justified is the purpose of this type of analysis?

Tolerance to glucose during pregnancy. Who is at risk

Among the risk factors that require additional testing in the form of a test to identify glucose tolerance, emit:

  • Excessive fullness of the pregnant woman (mass index exceeds the mark of 30).
  • During the blood sugar test, which was carried out when a pregnant woman was registered, the inclusion of glucose in the blood was recorded at a level above 5.1 mmol / l.
  • In the history of the presence of a violation in the form of gestational diabetes (during previous pregnancies).
  • Analysis of urine showed the presence of glucose in the urine during pregnancy.
  • The presence of pregnant relatives (relatives) with established pathology of diabetes.
  • The future mother bears a large fruit or the birth of a large baby took place in the past.
  • The age of the pregnant woman “crossed” the threshold of 35 years.

The presence of at least one of the factors listed above is in favor of the tolerance test. Moreover, the presence of “aggravating circumstances” is often an indication for the appointment of a glucose tolerant study twice - when a woman applies for registration (a classic sugar test) and in the second trimester of pregnancy.

Analysis for glucose in pregnancy: preparation for delivery of the analysis

Proper preparation for analysis is one of the most important components of a reliable research result.

  • A few days (three days are enough) before the test, the expectant mother should completely eliminate all fatty and spicy dishes, coffee, cakes, and smoked meats from her diet. By the way, such goodies for a woman "in position" should not be abused at other times. It is best to stick to a neutral diet.
  • Taking medication can also affect the results of the study, with the result that a false result will be obtained. Especially strictly this statement applies to: multivitamins, drugs containing iron, drugs to reduce pressure, diuretic drugs, corticosteroid hormones. When taking any medication, a pregnant woman is obliged to inform the doctor about the therapy.
  • It is very important to maintain the usual mode of motor activity, not to “lie down”, but also not too zealous.
  • The last meal on the eve of the test should occur at least 8 hours (and preferably 10-14 hours). In this period, you can only drink water.
  • It is also strictly forbidden to smoke and consume alcohol (which is already contraindicated for pregnant women).
  • Teeth should be cleaned overnight. It is better to skip this hygienic procedure before passing the analysis, since Some components of toothpaste can distort the test results.
  • Try to avoid increased anxiety and stressful situations.

Glucose level during pregnancy: decoding the results of the analysis

The interpretation of the test results is based on data obtained as a result of a three-time measurement of the level of glucose in the blood. Evaluating the result, you can rely on the following criteria:

1. Indicators of the concentration of sugar in the blood during the intake of biological material on an empty stomach and without load are:

  • below the mark of 5.1 - 5.5 mmol / l (taking into account the reference values ​​of the laboratory) - the norm
  • in the range of 5.6 - 6.0 mmol / l - deviations in glucose tolerance,
  • 6.1 mmol / l and more - suspicion of diabetes (in some laboratories, this figure is in the range of 7 mmol / l and above).

2. Measurement of glucose uptake after 60 minutes after additional loading with carbohydrates:

  • less than 10 mmol / l - normal
  • in the range of 10.1 - 11.1 mmol / l - deviations in glucose tolerance,
  • 11.1 mmol / l and more - suspicion of diabetes.

3. Fixing the sugar content 120 minutes after the glucose load:

  • less than 8.5 mmol / l indicates a rate
  • in the interval of 8.6 - 11.1 mmol / l - deviations in glucose tolerance,
  • 11.1 mmol / l and above - a clear deviation, possibly gestational diabetes.

How long is the survey?

The optimal period for the procedure is the 6–7th month. Most often, the test is passed at 25–29 weeks of gestation.

If the girl has indications for diagnosis, the study shall be submitted 1 time per trimester:

  1. In the early stages of gestation, glucose tolerance analysis is prescribed for 15–19 weeks.
  2. In the second trimester at 25-29 weeks.
  3. In the third trimester, up to 33 weeks of gestation.

General information

Glucose is a simple carbohydrate that enters the body with ordinary foods and is absorbed into the blood in the small intestine. It provides the nervous system, the brain and other internal organs and systems of the body with vital energy. For normal well-being and good productivity, glucose levels should remain stable. The hormones of the pancreas regulate its blood level: insulin and glucagon. These hormones are antagonists - insulin lowers sugar levels, and glucagon, on the contrary, increases.

Initially, the pancreas produces a proinsulin molecule, which is divided into 2 components: insulin and C-peptide. And if insulin after secretion remains in the blood for up to 10 minutes, then C-peptide has a longer half-life - up to 35-40 minutes.

On a note: until recently it was believed that C-peptide has no value for the body and does not perform any functions. However, the results of recent studies have revealed that C-peptide molecules have specific receptors on the surface that stimulate blood flow. Thus, determining the level of C-peptide can be successfully used to detect hidden disorders of carbohydrate metabolism.

When is it worth spending GTT

AgeHealth statusPeriodicity
over 45 years old
  • normal body weight
  • lack of risk factors
  • 1 time in 3 years with a normal result
over 16 years old
  • presence of one of the risk factors
  • body mass index more than 25 kg / m2
  • 1 time in 3 years with a normal result
  • Once a year with deviations from the norm

How to calculate BMI

BMI = (mass, kg): (height, m) 2

Values ​​are normal (no diabetes)

Glucose on an empty stomach4.1 - 5.9 mmol / l
Glucose after 30 min. after glucose load6.1 - 9.4 mmol / l
Glucose after 60 min. after glucose load6.7 - 9.4 mmol / l
Glucose after 90 min. after glucose load5.6 - 7.8 mmol / l
Glucose after 120 min. after glucose load4.1 - 6.7 mmol / l

Restrictions for carrying out GTT pregnant

Glucose tolerance test during pregnancy is prohibited in cases where the patient:

  • is in the phase of acute infectious disease,
  • Takes drugs that have a direct effect on blood glucose levels,
  • reached the third trimester (32 weeks).

The minimum period after the transfer of the disease or withdrawal of drugs and before the test is 3 days.

A limitation to the analysis is also an elevated glucose in the blood taken from the patient in the morning on an empty stomach (more than 5.1 mmol / l).

Also, the analysis is not performed when the patient has acute infectious and inflammatory diseases.

Features reduce the level of sugar

Symptoms of glucose deficiency in the body can be observed at a certain time of day (morning or evening), and their severity depends on the degree of decrease in blood glucose. If the amount of sugar fell to 3.4 mmol / l, then the person feels irritability, low tone, decreased performance and general weakness or lethargy. As a rule, to correct the condition, it is enough to take carbohydrate foods.

When the lack of sugars is associated with the development of diabetes, the patient feels:

  • drastic collapse
  • violation of thermoregulation and, as a consequence, hot flashes or chills,
  • increased sweating
  • frequent headaches and dizziness,
  • muscle weakness
  • decrease in concentration of attention and memory
  • frequent sensations of hunger, and after eating food - nausea,
  • drop in visual acuity.

Critical situations are accompanied by convulsions, uncharacteristic gait, convulsions, fainting and coma. It is important to pay attention to the manifestation of severe hypoglycemia and provide competent medical care.

The glucose tolerance analysis shows low values ​​if:

  • the patient is taking medications that help reduce the level of simple sugars, such as insulin,
  • The person being tested has insulinoma. The disease is accompanied by the formation of a neoplasm, which begins to actively secrete a substance similar to insulin. A third of the tumors occur in a malignant form with the spread of metastasis. The disease affects people of any age: from newborns to the elderly.

Prognosis of outcome depends on the nature of the tumor, with benign - full recovery is observed. Malignant neoplasms with metastases significantly worsen the prognosis. However, a high degree of sensitivity of mutant tissues to the effects of chemotherapeutic drugs should be emphasized.

Low values ​​are also recorded after a prolonged fasting of the patient being examined or after intense exercise. The diagnostic value of such results is small. The influence of external factors on the biochemical composition of the biomaterial should be excluded and the study should be repeated.

Is research required?

GTT analysis during pregnancy is mandatory for all women in the situation. This is due to the fact that gestational diabetes is diagnosed in them in 14% of cases. Many people mistakenly believe that this pathology only contributes to an increase in the size of the fetus and as a result leads to difficult childbirth.

But this is not all the complications that provokes the disease.

And it negatively affects both the health of the mother and the baby. Uncontrolled insulin deficiency leads to malfunction of the heart, liver, kidneys and brain. The neglected form of the disease can lead to miscarriage and the birth of a dead child.

Indicators that indicate gestational diabetes

GTT analysis is the main test that helps to identify carbohydrate imbalance during pregnancy.

The diagnosis of gestational diabetes is confirmed when there are at least 2 of the following symptoms:

  • the test conducted on an empty stomach showed a sugar level of more than 5.3 mmol / l,
  • a study after 1 h after the sugar load revealed a concentration of more than 10.0 mmol / l,
  • a blood test 2 hours after the use of a special solution showed 8.6 mmol / l,
  • data obtained after 3 hours exceeds the level of 7.7 mmol / l.

If at the first blood sampling of a future mother, a sugar index of 7.0 mmol / l was detected, then the diagnosis of gestational diabetes is established immediately. In this case, to conduct additional research with a load of sugar is prohibited, as it may adversely affect the well-being of the woman and the development of the fetus.

If there are any deviations from the norm after the test, the doctor prescribes a repeated analysis of GTT after several days, but within 2 consecutive weeks. If in this case, the study showed an excess of the concentration of sugar in the blood, the diagnosis is confirmed.

It is considered incorrect to take the results of the first testing as a basis, since a woman could simply ignore the recommendations for preparing for the test.

When results may be erroneous

Other provoking factors may also affect the reliability of the data obtained during the analysis of the GTT.

Therefore, sometimes the doctor questions the results if a pregnant woman has recorded:

  • lack of potassium, magnesium,
  • failure of the endocrine system,
  • development of systemic pathologies
  • stressful situations and emotional shock,
  • excessive physical activity, up to unhurried movement during the glucose tolerance analysis,
  • use of sugar, iron, and beta-blockers, glucocorticosteroids during the preparation phase.

The risk of deviations from the normal for the fetus

For a favorable course of pregnancy, it is very important that the placenta synthesizes in sufficient quantities the hormones cortisol, lactogen, estrogen. With normal insulin content, their synthesis does not interfere. But in conditions of its reduced production, this natural process is disturbed, since the pancreas does not fulfill its function in the required volume.

This feature has a negative impact not only on the health of the future mother, but on the development of the baby.

When the disease is diagnosed after 20 weeks, the risk of a negative impact on the formation of the fetus decreases, but the likelihood of fetal fetopathy increases. This means that the mass of the child will grow, as his pancreas is not able to function fully and therefore does not cope with the high concentration of sugar.

As a result, this leads to the proliferation of the shoulder girdle, liver, heart, and also provokes the growth of subcutaneous fat. The large size of the fetus is a prerequisite for protracted labor, since the overgrown shoulder girdle does not allow the baby to easily overcome the birth canal.

Prolonged delivery threatens hypoxia, injury, damage to the internal organs of the baby and the woman.

Another scenario can be triggered by the fact that the large size of the fetus inside the uterus leads to premature labor, when the intravenous systems and organs of the baby did not have time to fully form. Early labor is the most dangerous the fact that the lungs of the child are not able to breathe air from the outside, as they lack a sufficient amount of the necessary component - surfactant.

In this case, the child is placed in a special box for artificial ventilation of air in the lungs.

Names of the glucose tolerance test (oral glucose tolerance test, 75 g glucose assay, glucose tolerance test)

At present, the name of the method "glucose tolerant test (GTT)" is generally accepted in Russia. However, in practice, other names are also used to denote the same laboratory. diagnostic methodwhich are inherently synonymous with the term "glucose tolerance test". Such synonyms for the term GTT are the following: oral glucose tolerance test (OGTT), oral glucose tolerance test (OGTT), glucose tolerance test (TSH), as well as a sample with 75 g of glucose, sugar test, construction of sugar curves. In English, the name of this laboratory method is indicated by the terms glucose tolerance test (GTT), oral glucose tolerance test (OGTT).

What shows and why do we need a glucose tolerance test?

So, the glucose tolerance test is the determination of the level of sugar (glucose) in the blood on an empty stomach and two hours after taking a solution of 75 g of glucose dissolved in a glass of water. In some cases, an advanced glucose tolerance test is conducted, in which the blood sugar level is determined on an empty stomach, 30, 60, 90 and 120 minutes after consuming 75 g of glucose.

Normal blood sugar level on an empty stomach should range from 3.3 to 5.5 mmol / l for finger blood, and 4.0 to 6.1 mmol / l for blood from a vein. An hour after a person drinks 200 ml of liquid on an empty stomach in which 75 g of glucose is dissolved, the blood sugar level rises to the maximum level (8 - 10 mmol / l). Then, as the glucose is processed and assimilated, the blood sugar level decreases, and 2 hours after ingestion 75 g of glucose comes to almost normal, and is less than 7.8 mmol / l for finger and vein blood.

If, two hours after taking 75 g of glucose, the blood sugar level is higher than 7.8 mmol / l, but lower than 11.1 mmol / l, then this indicates a hidden violation of carbohydrate metabolism. That is, the fact that carbohydrates in a person’s body are absorbed with impairments is too slow, but so far these disorders are compensated and proceed covertly, without visible clinical symptoms. In fact, the abnormal level of blood sugar two hours after taking 75 g of glucose means that a person is already actively developing diabetes, but he has not yet acquired the classic unfolded form with all the characteristic symptoms. In other words, the person is already sick, but the stage of pathology is early, and therefore there are no symptoms yet.

Thus, it is obvious that the value of the glucose tolerant test is enormous, since this simple analysis makes it possible to identify the pathology of carbohydrate metabolism (diabetes mellitus) at an early stage, when there are no characteristic clinical symptoms, but it is possible to treat and prevent the formation of classical diabetes. And if the latent carbohydrate metabolic disturbances that are detected with the help of a glucose tolerant test can be corrected, reversed and prevented the development of the disease, then at the stage of diabetes, when the pathology is fully formed, it is already impossible to cure the disease, and you can only artificially maintain a normal sugar level in the blood, delaying the occurrence of complications.

It should be remembered that the glucose tolerance test allows detecting latent disorders of carbohydrate metabolism at an early stage, but makes it impossible to distinguish between the first and second diabetes mellitus, as well as the causes of the development of pathology.

Given the importance and diagnostic information of the glucose tolerant test, this analysis is justified to perform when there is a suspicion of a hidden violation of carbohydrate metabolism. Signs of such a hidden carbohydrate metabolism disorder are as follows:

  • Blood sugar is above normal, but below 6.1 mmol / l for finger blood and 7.0 mmol / l for blood from a vein,
  • Periodic appearance of glucose in the urine on the background of normal blood sugar levels,
  • Intense thirst, frequent and abundant urination, as well as increased appetite against the background of normal blood sugar,
  • The presence of glucose in the urine on the background of pregnancy, thyrotoxicosis, liver disease or chronic infectious diseases,
  • Neuropathy (nerve dysfunction) or retinopathy (retinal dysfunction) with unclear reasons.

If a person has signs of hidden disorders of carbohydrate metabolism, then he is recommended to do a glucose tolerance test to verify the presence or absence of an early stage of pathology.

Absolutely healthy people, whose blood sugar levels are normal and have no signs of hidden carbohydrate metabolism, do not need a glucose tolerance test, since it is completely useless. Also, there is no need to do a glucose tolerance test for those who have an empty stomach blood sugar level already corresponds to diabetes mellitus (more than 6.1 mmol / l for finger blood and more than 7.0 for vein blood), since they have obvious violations, not hidden.

Indications for glucose tolerance test

So, the glucose tolerant test is necessarily shown to be performed in the following cases:

  • Doubtful results of fasting glucose (below 7.0 mmol / l, but above 6.1 mmol / l),
  • Accidentally detected increase in blood glucose levels due to stress,
  • Accidentally detected presence of glucose in the urine against the background of normal blood sugar levels and the absence of diabetes mellitus (increased thirst and appetite, frequent and abundant urination),
  • The presence of signs of diabetes on the background of normal blood sugar levels,
  • Pregnancy (to detect gestational diabetes)
  • The presence of glucose in the urine on the background of thyrotoxicosis, liver disease, retinopathy or neuropathy.

If a person has any of the above situations, then he should definitely take the glucose tolerance test, as there is a very high risk of latent diabetes mellitus. And it is to confirm or refute such latent diabetes in such cases that the glucose tolerance test is performed, which allows you to “uncover” an imperceptible violation of carbohydrate metabolism in the body.

In addition to the above mandatory indications, there are a number of situations in which it is desirable for people to regularly donate blood for a glucose tolerant test, since they have a high risk of developing diabetes. Such situations are not mandatory indications for the delivery of the glucose tolerance test, but it is highly desirable to perform this analysis periodically in order to detect prediabetes or latent diabetes in a timely manner at an early stage.

Such situations in which it is recommended to periodically take the glucose tolerance test include the presence of the following diseases or conditions in a person:

  • Age over 45,
  • Body mass index more than 25 kg / cm 2,
  • The presence of diabetes mellitus in parents or blood brothers and sisters,
  • Sedentary lifestyle,
  • Gestational diabetes during past pregnancies,
  • Birth of a child weighing more than 4.5 kg
  • Premature labor, childbirth dead fruit, miscarriages in the past,
  • Arterial hypertension,
  • The level of HDL is below 0.9 mmol / l and / or triglycerides above 2.82 mmol / l,
  • The presence of any pathology of the cardiovascular system (atherosclerosis, coronary heart disease, etc.),
  • Polycystic ovary,
  • Gout,
  • Chronic periodontal disease or furunculosis,
  • Reception of diuretic, glucocorticoid hormones and synthetic estrogens (including as part of combined oral contraceptives) for a long period of time.

If a person does not have any of the above conditions or diseases, but his age is over 45 years old, then he is recommended to take a glucose tolerance test once every three years.

If a person has at least two states or diseases of the above, then it is recommended that he pass the glucose tolerance test without fail. If the test value turns out to be normal, then it should be taken as part of a preventive examination every three years. But when the test results are not normal, you need to carry out treatment prescribed by the doctor and take an analysis once a year to monitor the condition and progression of the disease.

Contraindications to the implementation of glucose tolerance test

Glucose tolerance test is contraindicated for absolutely those who suffer from previously diagnosed diabetes, and when the fasting blood sugar level is 11.1 mmol / l or higher! In this situation, GTT is never performed, since the glucose load can provoke the development of hyperglycemic coma.

Also, the glucose tolerance test is contraindicated in cases where there are factors that can affect its result and make it inaccurate, that is, false positive or false negative. But in such cases, the contraindication is usually temporary, acting until the factor that influences the test result disappears.

So, the glucose tolerance test is not performed in the following cases:

  • The acute period of any disease, including infectious (for example, SARS, aggravation of gastric ulcer, intestinal upset, etc.),
  • Myocardial infarction, suffered less than a month ago,
  • A period of severe stress in which a person is located
  • Trauma, childbirth or surgery, less than 2 to 3 months ago,
  • Alcoholic cirrhosis of the liver,
  • Hepatitis,
  • Period of menstruation in women
  • Gestational age more than 32 weeks
  • Medications that increase blood sugar levels (adrenaline, caffeine, rifampicin, glucocorticoid hormones, thyroid hormones, diuretics, oral contraceptives, antidepressants, psychotropic drugs, beta-blockers (atenolol, bisoprolol, etc.). Before taking the glucose tolerant test, you must stop taking these drugs for at least three days.

How to take a glucose tolerant test?

The patient comes to the laboratory, where on an empty stomach blood is taken from his finger or from a vein to determine the level of glucose (hungry). After that, prepare a solution of glucose, and give to drink within five minutes in small sips. If the solution seems subjectively sugary sweet and overly nasty, then add a little citric acid or freshly squeezed lemon juice.

After the glucose solution is drunk, note the time, and the patient is seated in a comfortable posture and asked to spend the next two hours quietly sitting in a medical institution, without engaging in any active work. It is advisable to just read your favorite book these two hours. For two hours after taking the glucose solution, you can not eat, drink, smoke, use alcohol and energy, exercise, get nervous.

Two hours after taking the glucose solution, blood is taken again from a vein or from a finger and the concentration of sugar in the blood is determined. It is the value of blood sugar two hours after taking the glucose solution that is the result of the glucose tolerance test.

In some cases, an advanced glucose tolerance test is performed, in which blood is taken from a finger or from a vein 30, 60, 90 and 120 minutes after taking a glucose solution. Each time in the blood, the sugar level is determined, and the values ​​obtained are plotted on a graph, where time is plotted along the X axis, and blood sugar concentration is plotted along the Y axis. The result is a graph in which the normal blood sugar level is maximal 30 minutes after taking the glucose solution, and after 60 and 90 minutes the blood sugar levels are constantly decreasing, reaching practically lean values ​​of the sugar level by the 120th minute.

When blood is collected from a finger two hours after taking a glucose solution, the study is considered completed. After that, you can go and do all your business during the day.

The glucose solution for the glucose tolerance test is prepared in the same type - a certain amount of glucose is dissolved in a glass of water. But the amount of glucose can be different, and depends on the age and body weight of the person.

For example, adults of normal build with normal body weight dissolve 75 g of glucose in 200 ml of water. Very fat adults take a dose of glucose individually from a ratio of 1 g of glucose per 1 kg of weight, but not more than 100 g. For example, if a person weighs 95 kg, then the dose of glucose is 95 * 1 = 95 g. And it is 95 g that is dissolved in 200 ml of water, and give to drink. If a person weighs 105 kg, then the estimated dose of glucose for him is 105 g, but for the test a maximum of 100 g can be dissolved. Hence, for a patient with a body weight of 105 kg, the dose of glucose is 100 g, which is dissolved in a glass of water and allowed to drink .

Children whose body weight is less than 43 kg, the dose of glucose is also calculated individually, based on the ratio of 1.75 g per 1 kg of weight. For example, a child weighs 20 kg, which means that the dose of glucose for him is 20 * 1.75 g = 35 g. Thus, for a child weighing 20 kg, 35 g of glucose is dissolved in a glass of water. Children with a body weight of more than 43 kg are given the usual adult dosage of glucose, namely, 75 g per cup of water.

After glucose tolerance test

When the delivery of the glucose tolerant test is completed, you can have breakfast with what you want, have a drink, and also return to smoking and drinking alcoholic beverages. In general, glucose loading usually does not cause deterioration of health and does not negatively affect the state of the reaction rate, and therefore, after a glucose tolerant test, you can do all your business, including working, driving a car, learning, etc.

Glucose Tolerance Test Results

The glucose tolerant test results are two digits: one is the fasting blood sugar level, and the second is the blood sugar value two hours after taking the glucose solution.

If the advanced glucose tolerance test was performed, then the result is five digits. The first digit is the fasting blood sugar level. The second digit is the blood sugar level 30 minutes after taking the glucose solution, the third digit is the sugar level one hour after taking the glucose solution, the fourth digit is blood sugar after 1.5 hours, and the fifth digit is blood sugar after 2 hours.

The obtained values ​​of blood sugar on an empty stomach and after taking a glucose solution are compared with normal ones, and it is concluded that there is a presence or absence of a pathology of carbohydrate metabolism.

Norm glucose tolerance test

Normally, the fasting blood glucose level is 3.3 - 5.5 mmol / l for finger blood, and 4.0 - 6.1 mmol / l for vein blood.

Two hours after taking a glucose solution, the normal blood sugar level is less than 7.8 mmol / l.

The level of sugar in the blood after half an hour after taking the glucose solution should be lower than in an hour, but higher than on an empty stomach, and should be about 7–8 mmol / l.

The blood sugar level one hour after taking the glucose solution should be the highest, and should be about 8 - 10 mmol / l.

The sugar level after 1.5 hours after taking the glucose solution should be the same as after half an hour, that is, about 7 - 8 mmol / l.

Decoding of glucose tolerance test

According to the results of the glucose tolerance test, a doctor can take out three options for a conclusion - norm, prediabetes (impaired glucose tolerance) and diabetes mellitus. The values ​​of sugar levels on an empty stomach and two hours after taking the glucose solution, corresponding to each of the three variants of conclusions, are given in the table below.

The nature of carbohydrate metabolismFasting blood sugarBlood sugar two hours after taking glucose solution
Norm3.3 - 5.5 mmol / l for finger blood
4.0 - 6.1 mmol / l for blood from a vein
4.1 - 7.8 mmol / l for finger and vein blood
Pre-diabetes (impaired glucose tolerance)Less than 6.1 mmol / l for finger blood
Less than 7.0 mmol / l for blood from a vein
6.7 - 10.0 mmol / l for finger blood
7.8 - 11.1 mmol / l for blood from a vein
DiabetesMore than 6.1 mmol / l for finger blood
More than 7.0 mmol / l for blood from a vein
More than 10.0 mmol / l for finger blood
More than 11.1 mmol / l for blood from a vein

To understand what result a particular person received according to the glucose tolerant test, you need to look at the limits of the sugar levels for his analyzes. Next, see what (norm, prediabetes, or diabetes) include the range of values ​​of sugar, which were included in their own analyzes.

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Where do the glucose tolerance test?

The glucose tolerance test is performed in almost all private laboratories and in laboratories of ordinary public hospitals and clinics. Therefore, it is easy to do this research - it is enough to contact a state or private clinic laboratory. However, government laboratories often do not have glucose for the test, and in this case you will need to buy glucose powder yourself at the pharmacy, bring it with you, and medical staff will make a solution and perform the test. Glucose powder is usually sold in state pharmacies that have a prescription department, and in private pharmacy chains it is practically absent.

Watch the video: Glucose Tolerance Test: Expected normal results (February 2020).