Glucose tolerance test decoding. How to perform a glucose tolerance test (instructions, transcript)

Oral glucose tolerance test (extended) consists of determining plasma glucose levels on an empty stomach and every 30 minutes (30, 60, 90, 120 minutes) after a carbohydrate load in order to diagnose various disorders carbohydrate metabolism (diabetes mellitus, impaired glucose tolerance, fasting glycemia).

The research results are provided with a free doctor’s commentary.

Synonyms Russian

Oral glucose tolerance test (OGTT), a test for glucose tolerance, a test with 75 grams of glucose.

SynonymsEnglish

Glucose tolerance test (GTT), oral glucose tolerance test ( OGTT).

Research method

Enzymatic UV method (hexokinase).

Units

Mmol/L (millimoles per liter), mg/dL (mmol/L x 18.02 = mg/dL).

What biomaterial can be used for research?

Venous blood.

How to properly prepare for research?

• An oral glucose tolerance test should be performed in the morning after at least 3 days of unrestricted nutrition (more than 150 g of carbohydrates per day) and normal physical activity. The test should be preceded by an overnight fast for 8-14 hours (you can drink water).
• Last evening reception food should contain 30-50 grams of carbohydrates.
• Do not drink alcohol 10-15 hours before the test.
• Do not smoke the night before the test and until it is over.

General information about the study

An oral glucose tolerance test should be performed in the morning after at least 3 days of unrestricted nutrition (more than 150 g of carbohydrates per day) and normal physical activity. The test should be preceded by an overnight fast for 8-14 hours (you can drink water). The last evening meal should contain 30-50 g of carbohydrates. Do not smoke the night before the test and until it is over. After drawing blood on an empty stomach, the subject should no more than 5 minutes. drink 75 g of anhydrous glucose or 82.5 g of glucose monohydrate dissolved in 250-300 ml of water. For children, the load is 1.75 g of anhydrous glucose (or 1.925 g of glucose monohydrate) per kg of body weight, but not more than 75 g (82.5 g), with a child weighing 43 kg or more given usual dose(75 g). Smoking and vigorous physical activity are not allowed during the test. Blood is taken every 30 minutes (30, 60, 90, 120 minutes) with the determination of hyperglycemic and postglycemic coefficients.

It should be remembered that if the fasting blood glucose level exceeds 7.0 mmol/l, then the oral glucose tolerance test is not performed, since this blood glucose level itself is one of the criteria for diagnosing diabetes mellitus.

An oral glucose tolerance test allows you to diagnose various disorders of carbohydrate metabolism, such as diabetes mellitus, impaired glucose tolerance, fasting glycemia, but cannot clarify the type and causes of diabetes mellitus, and therefore, after receiving any result of an oral glucose tolerance test, it is advisable to conduct a mandatory consultation endocrinologist.

A distinctive feature of this is that it is performed not at two, but at five points (on an empty stomach and every 30 minutes: 30, 60, 90, 120 minutes) with the determination of hyperglycemic and postglycemic coefficients.

What is the research used for?

For diagnostics:

• diabetes mellitus;
• impaired glucose tolerance,
• fasting glucose disorders.

When is the study scheduled?

• In case of questionable glycemic values, to clarify the state of carbohydrate metabolism;
• when examining patients with risk factors for developing diabetes mellitus:
  • age over 45 years;
  • BMI more than 25 kg/m2;
  • family history of diabetes (parents or siblings with type 2 diabetes);
  • habitually low physical activity;
  • presence of fasting glucose or a history of impaired glucose tolerance;
  • gestational diabetes mellitus or a history of birth of a fetus weighing more than 4.5 kg;
  • arterial hypertension (of any etiology);
  • lipid metabolism disorder (HDL level below 0.9 mmol/l and/or triglyceride level above 2.82 mmol/l);
  • the presence of any disease of the cardiovascular system.

When is it appropriate to perform an oral glucose tolerance test to screen for carbohydrate metabolism disorders?

When should an oral glucose tolerance test not be performed?

• Against the background of any acute disease, including infectious.
• While taking medications that increase glycemic levels (glucocorticoids, thyroid hormones, thiazides, beta blockers, oral contraceptives). Cancellation is required (according to doctor's recommendations) 3 days before the test.

What do the results mean?

Reference values

Reasons for increased blood glucose levels:

• various disorders of carbohydrate metabolism (diabetes mellitus, impaired glucose tolerance, fasting glycemia);
• false positive result – recent or transferable acute illness, surgical operations or any other stressful situation, reception medicines that increase glycemic levels (glucocorticoids, thyroid hormones, thiazides, beta blockers, oral contraceptives).

Reasons for low blood plasma glucose levels:

• taking medications that reduce glycemic levels (insulin, various sugar-lowering drugs);
• insulinoma;
• excessive fasting;

What can influence the result?

General urine analysis with sediment microscopy

Who orders the study?

Doctor general practice, therapist, endocrinologist, cardiologist, nephrologist, as well as doctors of other specialties.

Literature

• Clinical recommendations “Algorithms for specialized medical care patients with diabetes." Edited by I.I. Dedova, M.V. Shestakova, A.Yu. Mayorova 8th issue, M., 2017.
• Definition and diagnosis of diabetes mellitus and intermediate hyperglycemia. Report of a WHO/IDF ConsultatIon.2006.

A glucose tolerance test is a special test that makes it possible to check the performance of the pancreas. Its essence boils down to the fact that a certain dose of glucose is injected into the body and after 2 hours, blood is drawn for analysis. This test may also be called a glucose load test, a sugar load test, a GTT test, or a GNT test.

The human pancreas produces a special hormone called insulin, which can effectively monitor blood sugar levels and reduce them. If a person has diabetes, 80 or even 90 percent of all beta cells will be affected.

The glucose tolerance test can be oral and intravenous, and the second type is performed extremely rarely.

Who is a glucose test indicated for?

A glucose tolerance test for sugar tolerance must be performed at normal and borderline glucose levels. This is important for differentiating diabetes mellitus and identifying the degree of glucose tolerance. This condition may also be called prediabetes.

In addition, a glucose tolerance test can be prescribed for those individuals who have had hyperglycemia at least once during stressful situations, for example, a heart attack, stroke, or pneumonia. GTT will be carried out only after the patient’s condition has normalized.

Speaking of norms, on an empty stomach good indicator will be from 3.3 to 5.5 millimoles per liter of human blood, inclusive. If the test results in a figure higher than 5.6 millimoles, then in such situations we will be talking about impaired fasting glycemia, and with a result of 6.1 diabetes mellitus develops.

What should you pay special attention to?

It is worth noting that the usual results of using glucometers will not be indicative. They can provide fairly average results, and are recommended only during the treatment of diabetes mellitus in order to control the level of glucose in the patient’s blood.

We must not forget that blood is drawn from the cubital vein and finger at the same time, and on an empty stomach. After eating, sugar is perfectly absorbed, which leads to a decrease in its level to as much as 2 millimoles.

The test is a fairly serious stress test and that is why it is highly recommended not to perform it unless absolutely necessary.

Who is the test contraindicated for?

The main contraindications for performing a glucose tolerance test include:

• severe general condition;
• inflammatory processes in the body;
• disturbances in the process of eating after surgical intervention on the stomach;
• acid ulcers and Crohn's disease;
• acute stomach;
• exacerbation of hemorrhagic stroke, cerebral edema and heart attack;
• failures in normal operation liver;
• insufficient intake of magnesium and potassium;
• use of steroids and glucocorticosteroids;
• tablet contraceptives;
• Cushing's disease;
• hyperthyroidism;
• taking beta blockers;
• acromegaly;
• pheochromocytoma;
• taking phenytoin;
• thiazide diuretics;
• use of acetazolamide.

How to prepare the body for a high-quality glucose tolerance test?

In order for the results of the test for the body's resistance to glucose to be correct, it is necessary in advance, namely several days before the test, to consume only those foods that are characterized by normal or increased level carbohydrates.

We are talking about food that contains 150 grams or more. If you follow a low-carbohydrate diet before the test, this will be a serious mistake, because the result will be an excessively low reading of the patient's blood sugar level.

In addition, approximately 3 days before the proposed study, the use of the following drugs is not recommended: oral contraception, thiazide diuretics, as well as glucocorticosteroids. You should not drink at least 15 hours before GTT alcoholic drinks and eat food.

How the test is carried out

A glucose tolerance test for sugar levels is performed in the morning on an empty stomach. You should also not smoke cigarettes before or until the end of the test.

First, blood is drawn from the ulnar vein on an empty stomach. After this, the patient must drink 75 grams of glucose, previously dissolved in 300 milliliters clean water without gas. All liquid should be consumed within 5 minutes.

If we're talking about about the subject being studied childhood, then in this case glucose is diluted at the rate of 1.75 grams per kilogram of the child’s weight, and you need to know what it is. If his weight is more than 43 kg, then a standard dosage for an adult is required.

Glucose levels will need to be measured every half hour to avoid missing blood sugar peaks. At any such moment, its level should not exceed 10 millimoles.

It is worth noting that during the glucose test, any physical activity is indicated, and not just lying or sitting in one place.

Why might I get incorrect test results?

The following factors can lead to false negative results:

• impaired absorption of glucose into the blood;
• absolute restriction of carbohydrates on the eve of the test;
• excessive physical activity.

A false positive result can be obtained in the following cases:

• prolonged fasting of the patient being studied;
• due to compliance with the pastel regime.

How are glucose test results evaluated?

According to the World Health Organization from 1999, the results shown by a glucose tolerance test performed on capillary whole blood will be as follows:

18 mg/dL = 1 millimole per 1 liter of blood,

100 mg/dL = 1 g/L = 5.6 millimoles,

dl = deciliter = 0.1 l.

On empty stomach:

• the norm will be considered: less than 5.6 mmol/l (less than 100 mg/dl);
• with impaired fasting glucose: from 5.6 to 6.0 millimoles (from 100 to less than 110 mg/dL);
• for diabetes mellitus: the norm is more than 6.1 mmol/l (more than 110 mg/dl).

2 hours after consuming glucose:

• normal: less than 7.8 millimoles (less than 140 mg/dL);
• impaired tolerance: from 7.8 to 10.9 millimoles (ranging from 140 to 199 mg/dL);
• diabetes mellitus: greater than 11 millimoles (greater than or equal to 200 mg/dL).

When determining the sugar level from blood taken from the ulnar vein on an empty stomach, the values ​​will be the same, and after 2 hours this figure will be 6.7-9.9 millimoles per liter.

Pregnancy test

The described glucose tolerance test will be incorrectly confused with the one that is carried out in pregnant women in the period from 24 to 28 weeks of pregnancy. It is prescribed by a gynecologist to identify risk factors for the development of latent diabetes in pregnant women. In addition, such diagnostics can be recommended by an endocrinologist.

IN medical practice exist various options test: one-hour, two-hour and one that lasts 3 hours. If we talk about the indicators that should be set when taking blood on an empty stomach, then these will be numbers not lower than 5.0.

If a pregnant woman has diabetes mellitus, then the following indicators will indicate it:

• after 1 hour - more or equal to 10.5 millimoles;
• after 2 hours - more than 9.2 mmol/l;
• after 3 hours - more or equal to 8.

During pregnancy, it is extremely important to constantly monitor blood sugar levels, because in this position the child in the womb is subject to double stress, and in particular, its pancreas. Plus, everyone is interested in the question...

Diagnosis of the body - special laboratory method to determine diabetes mellitus (DM) and its preexisting conditions. There are two types:

• intravenous glucose test;
• oral glucose tolerance test.

The analysis shows how the human body dissolves glucose in the blood. We will consider the nuances, methods and feasibility of the glucose tolerance test below. You'll find out what the norm is this study and its pitfalls.

Glucose is a monosaccharide used by the body to maintain vital energy. If a person has diabetes that has never been treated, there is a large amount of the substance in the blood. The test is needed for timely diagnosis disease and initiation of treatment early stage. We will explain below how tolerance testing is carried out.

If the analysis shows high level– a person has type 2 diabetes. Pregnant women should not be afraid, because with an “interesting position” the concentration of sugar in the blood increases.

Testing glucose tolerance is a simple procedure that should be carried out regularly as a preventive measure.

Why take the test and who is prescribed the test

The significance of the study is difficult to overestimate. The analysis reveals the feasibility of carrying out other manipulations necessary for diagnosing diabetes mellitus. Particular attention is paid to pregnant women, as well as people prone to diabetes. They do the test for safety and health reasons.

Preparing for the test

The test is preceded by careful preparation. Before the first test for glucose tolerance, doctors recommend following a diet: exclude fatty, spicy food and foods high in carbohydrates. Eat 4-5 times a day (breakfast, lunch, dinner and 1-2 snacks) without overeating or fasting - saturate the body useful substances For normal life must be complete.

How to get tested for glucose tolerance? Exclusively on an empty stomach: avoid eating for 8 hours. But you shouldn’t overdo it: fasting is allowed for no more than 14 hours.

The day before the glucose tolerance test, completely give up alcohol and cigarettes.

Before preparing for the study, consult your doctor about taking medications. The test will be inaccurate if you take pills that affect blood sugar. These include medications that contain:

• caffeine;
• adrenalin;
• glucocorticoid substances;
• thiazide diuretics, etc.

How to perform a glucose tolerance test

The doctor who will perform the procedure will explain how to take a glucose tolerance test. Let's talk briefly about the features of the test. First, let's look at the specifics of the oral method.

A blood sample is taken for analysis. The patient drinks water containing a certain amount of glucose (75 grams). Then the doctor takes blood for analysis every half hour to hour. The procedure takes about 3 hours.

The second method is used quite rarely. It's called an intravenous blood sugar test. Its peculiarity is that it is prohibited from being used for diagnosing diabetes. A blood test using this method is performed as follows: the substance is injected into the patient’s vein within three minutes, after first determining the insulin level.

After making the injection, the doctor counts at 1 and 3 minutes after injection. The measurement time depends on the doctor’s point of view and the method of the procedure.

Feelings during the test

When performing a glucose tolerance test, glucose tolerance cannot be excluded. discomfort. Don't be alarmed: this is the norm. The study is characterized by:

• increased sweating;
• dyspnea;
• slight nausea;
• fainting or pre-fainting state.

As practice shows, the glucose tolerance test causes side effects quite rare. Before taking the test, calm down and do auto-training. Nervous system stabilizes and the procedure will pass without complications.

What is the norm for a glucose tolerance test?

Before the study, familiarize yourself with the standards of analysis to roughly understand the results. The unit of measurement is milligrams (mg) or deciliters (dl).

Normal at 75 gr. substances:

• 60-100 mg - initial result;
• 200 mg after 1 hour;
• up to 140 mg after a couple of hours.

Remember that the units of measurement for determining blood sugar levels vary by laboratory - check with your doctor for this information.

The test sometimes shows far from rosy results. Don't be discouraged if the indicators are not within the norm. We need to find out the cause and solve the problem.

If blood sugar exceeds 200 mg (dm), the patient has diabetes.

The diagnosis is made exclusively by a doctor: high sugar levels are possible with other diseases (Cushing's syndrome, etc.).

The importance of analysis is difficult to overestimate. A person’s well-being depends on the level of glucose; this indicator must be kept under control. If you want to enjoy life and be constantly active, you shouldn't ignore your blood sugar.

A general practitioner can give a referral for a glucose tolerance test. family doctor, an endocrinologist and even a neurologist with a dermatologist - it all depends on which specialist suspects a patient with impaired glucose metabolism.

When GTT is prohibited

The test stops if the fasting blood glucose level (GLU) exceeds the threshold of 11.1 mmol/L. Additional intake of sweets in this condition is dangerous, it causes disturbances in consciousness and can lead to.

Contraindications for the glucose tolerance test:

1. For acute infectious or inflammatory diseases.
2. In the last trimester of pregnancy, especially after 32 weeks.
3. Children under 14 years old.
4. During the period of exacerbation chronic pancreatitis.
5. In the presence of endocrine diseases, causing growth blood glucose: Cushing's disease, increased activity thyroid gland, acromegaly, pheochromocytoma.
6. While taking medications that can distort test results - steroid hormones, COCs, diuretics from the hydrochlorothiazide group, diacarb, some antiepileptic drugs.

In pharmacies and medical equipment stores you can buy glucose solution, inexpensive glucometers, and even portable biochemical analyzers that determine 5-6 blood parameters. Despite this, it is prohibited to test glucose tolerance at home without medical supervision. Firstly, such independence can lead to sharp deterioration state right up to calling an ambulance.

Secondly, the accuracy of all portable instruments is insufficient for this analysis, so the results obtained in a laboratory setting may differ significantly. These devices can be used to determine sugar on an empty stomach and after a natural glucose load - a normal meal. It is convenient to use them to identify foods that have the maximum effect on blood sugar levels and create a personal diet to prevent diabetes or compensate for it.

It is also undesirable to undergo both oral and intravenous glucose tolerance tests frequently, since they place a serious burden on the pancreas and, if performed regularly, can lead to its depletion.

Factors influencing the reliability of GTT

When taking the test, the first measurement of glucose is taken on an empty stomach. This result is considered the level to which other measurements will be compared. The second and subsequent indicators depend on the correctness of glucose administration and the accuracy of the equipment used. We cannot influence them. But for the reliability of the first measurement The patients themselves are entirely responsible. A number of reasons can distort the results, so preparation for the GTT should be given Special attention.

The following may lead to inaccurate data obtained:

1. Alcohol on the eve of the study.
2. Diarrhea, extreme heat, or not drinking enough water that has led to dehydration.
3. Difficult physical work or intense training for 3 days before the test.
4. Sudden changes in diet, especially those related to carbohydrate restriction and fasting.
5. Smoking at night and in the morning before GTT.
6. Stressful situations.
7. Colds, including the lungs.
8. Regenerative processes in the body in postoperative period.
9. Bed rest or a sharp decrease in usual physical activity.

When receiving a referral for analysis, the attending physician must be informed about all medications taken, including contraceptives. He will choose which ones will have to be canceled 3 days before the GTT. Usually these are drugs that lower sugar, contraceptives and others. hormonal agents.

Test procedure

Although the glucose tolerance test is very simple, you will have to spend about 2 hours in the laboratory, during which changes in sugar levels will be analyzed. It will not be possible to go for a walk at this time, as staff supervision is required. Typically, patients are asked to wait on a bench in the laboratory hallway. Playing exciting games on your phone is also not worth it - emotional changes can affect the absorption of glucose. The best choice- an educational book.

Stages of identifying glucose tolerance:

1. The first blood donation must be done in the morning, on an empty stomach. The period since the last meal is strictly regulated. It should not be less than 8 hours, so that the consumed carbohydrates have time to be utilized, and no more than 14, so that the body does not begin to starve and absorb glucose in non-standard quantities.
2. Glucose load represents a glass sweet water, which must be drunk within 5 minutes. The amount of glucose in it is determined strictly individually. Typically, 85 grams of glucose monohydrate is dissolved in water, which equates to 75 grams pure. For persons 14-18 years old, the required load is calculated based on their weight - 1.75 g of pure glucose per kilogram of weight. If you weigh more than 43 kg, regular adult dose. For obese people, the load is increased to 100 g. intravenous administration the portion of glucose is greatly reduced, which makes it possible to take into account its losses during digestion.
3. Blood is donated again 4 more times - every half hour after exercise. Based on the dynamics of sugar reduction, one can judge about disturbances in its metabolism. Some laboratories take blood twice - on an empty stomach and after 2 hours. The result of such an analysis may be unreliable. If your blood glucose peak occurs more than early time, it will remain unregistered.

An interesting detail - they add to sweet syrup citric acid or just give a slice of lemon. Why lemon and how does it affect the measurement of glucose tolerance? It does not have the slightest effect on sugar levels, but it allows you to eliminate nausea after a one-time intake of a large amount of carbohydrates.

Laboratory determination of glucose levels

Currently, blood is almost never taken from a finger. In modern laboratories the standard is to work with venous blood. When analyzing it, the results are more accurate, since it is not mixed with intercellular fluid and lymph, like capillary blood from a finger. Nowadays, sampling from a vein is no less traumatic than the procedure - laser-sharpened needles make the puncture almost painless.

When blood is collected for a glucose tolerance test, it is placed in special tubes treated with preservatives. The best option– the use of vacuum systems, into which blood flows evenly due to the difference in pressure. This avoids the destruction of red blood cells and the formation of clots, which can distort the test results or make it impossible to perform it altogether.

The laboratory assistant’s task at this stage is to avoid blood damage - oxidation, glycolysis and coagulation. To prevent the oxidation of glucose, sodium fluoride is contained in the test tubes. Fluorine ions in it prevent the breakdown of the glucose molecule. Changes in glycated hemoglobin are avoided by using cool tubes and subsequent refrigeration of samples. EDTA or sodium citrate are used as anticoagulants.

The tube is then placed in a centrifuge, which separates the blood into plasma and shaped elements. The plasma is transferred to a new tube, where the glucose level will be determined. Many methods have been developed for this purpose, but two of them are currently used in laboratories: glucose oxidase and hexokinase. Both methods are enzymatic, their action is based on chemical reactions of enzymes with glucose. The substances obtained as a result of these reactions are examined using a biochemical photometer or automatic analyzers. Such a well-established and proven blood analysis process allows you to obtain reliable data on its composition, compare results from different laboratories, and use uniform glucose levels.

Normal GTT indicators

Glucose norms for the first blood draw during GTT

Glucose norms for the second and subsequent blood draws during GTT

The data obtained is not a diagnosis, it is just information for the attending physician. To confirm the results, a repeat glucose tolerance test is performed, blood donation is prescribed for other indicators, additional research organs. Only after all these procedures can we talk about metabolic syndrome, impaired glucose absorption and, especially, diabetes mellitus.

If the diagnosis is confirmed, you will have to reconsider your entire lifestyle: bring your weight back to normal, limit carbohydrate foods, restore muscle tone through regular physical activity. In addition, patients are prescribed hypoglycemic drugs, and severe cases and insulin injections. A large number of blood glucose causes a feeling constant fatigue and apathy, poisons the body from the inside, provokes a difficult to overcome desire to overeat sweets. The body seems to resist recovery. And if you succumb to it and let the disease take its course, there is a high risk of getting irreversible changes in the eyes, kidneys, feet, and even disability within 5 years.

If you belong to a risk group, diabetes prevention should begin even before a glucose tolerance test shows abnormalities. In this case, the probability of a long and healthy life without diabetes increases significantly.

Glucose tolerance test during pregnancy

If someone says that pregnant women do not need to undergo GTT, this is completely wrong!

Pregnancy is a time of radical restructuring of the body for good nutrition the fetus and providing it with oxygen. Changes also occur in glucose metabolism. In the first half of the pregnancy, GTT gives lower values ​​than usual. Then a special mechanism is activated - some muscle cells stop recognizing insulin, more sugar remains in the blood, and the child receives more energy through the bloodstream for growth.

If this mechanism fails, it is referred to as gestational diabetes. This separate species diabetes mellitus, which occurs exclusively during pregnancy and goes away immediately after birth.

It poses a danger to the fetus due to disruption of blood flow through the vessels of the placenta, increased risk infections, and also leads to high weight of the child, as a result of which the course of labor is complicated.

Criteria for diagnosing gestational diabetes

If fasting glucose is above 7, and after exercise – 11 mmol/l, it means that diabetes mellitus debuted during pregnancy. Such high rates will not be able to return to normal after the birth of the child.

Let's figure out how long it takes to do GTT in order to track metabolic disorders in time. The first time sugar tests are prescribed immediately after visiting a doctor. Blood glucose or glycated hemoglobin is determined. Based on the results of these studies, pregnant women with diabetes are identified (glucose above 7, glycated hemoglobin more than 6.5%). Their pregnancy is carried out in a special order. If questionable borderline results are obtained, pregnant women are considered to be at risk for gestational diabetes. Glucose tolerance test for early stages It is performed for women from this group, as well as for those who have a combination of several risk factors for diabetes mellitus.

The test at 24-28 weeks of pregnancy is mandatory for everyone; it is part of the screening examination.

A glucose tolerance test is performed during pregnancy with great caution, since high sugar after exercise can harm the fetus. A rapid test is first carried out to detect glucose levels, and only if their levels are normal, GTT is allowed. Glucose use no more than 75 g, at the slightest infectious diseases the test is canceled, a load test is performed only up to 28 weeks, in exceptional cases - up to 32.

Glucose tolerance test- a multi-stage and rather complex, but quite informative research method. Most often it is prescribed to people at risk of diabetes or (diagnosed disease in close relatives, obesity, pregnancy).

The advantage of the glucose tolerance test is that the level of carbohydrates in the blood is determined on an empty stomach and after taking a glucose solution.

Thus, it is possible to identify not only the initial level of sugar in the blood, but also to monitor the body’s need for it.

Types of tests

In addition to the standard glucose tolerance test, if the results are questionable, the doctor may prescribe prednisolone glucose tolerance test, which is a type of glucose tolerance test using corticosteroids.

There are also differences in the concentration of the glucose solution used for the test. For example, for adults a syrup of 75 g of glucose is used, and for children - at the rate of 1.75 g per kg of body weight.

Indications for use

To carry out its functions, our body needs energy, the main substrate of which is glucose. Normally, its amount in the blood can range from 3.5 mmol/l to 5.5 mmol/l.

In the case when the sugar level, according to the results of a standard blood test, rises above the upper limit of normal, they speak of a prediabetic state, and after a critical increase in its level (over 6.1 mmol/l), the patient is at risk and special tests are prescribed.

Several factors can affect blood glucose levels:

• Poor nutrition with a predominance of foods rich in refined sugar;
• Stress;
• Alcohol abuse;
• Lack of physical activity;
• Endocrine diseases;
• Genetic predisposition;
• Pregnancy;
• Obesity.

In accordance with this, the risk group is determined.

Methodology

Twelve hours before the glucose tolerance test (standard), you should refuse to eat and try to reduce your intake of liquids.

It is strictly forbidden to drink alcohol the day before the study, smoke, or drink coffee.

Glucose tolerance test It is not advisable to carry out during menstruation. You should limit your intake of medications on the eve of the test, as some can increase glucose levels (corticosteroids, oral contraceptives, rifampicin, albuterol), while others (aspirin, antihistamines, spironolactone) on the contrary - reduce.

Glucose tolerant no test performed in the presence of diseases in acute form(cold, ARVI, exacerbation chronic diseases). Patients with asthma, angina pectoris, or a recent stroke or heart attack are given glucose solution instead of simple carbohydrates in a dose of twenty grams.

At first the initial sugar level is determined. To do this, the first portion of blood is taken from a vein on an empty stomach. Next, the patient is given a portion of glucose (calculated based on their age group). For the next two hours, you are prohibited from eating, smoking, drinking, or performing physical exercise. Otherwise, the sample results are considered invalid.

Second portion of blood from a vein shows the ability of body cells to consume glucose molecules. In diabetes mellitus, the results of the second test increase noticeably and practically do not decrease over time.

Norms and decoding

When performing a glucose tolerance test considered the norm, if the amount of sugar in the first portion of blood is within 5.5 mmol/l, and in the second - less than 7.8 mmol/l.

If in the first sample the amount of glucose is 5.5 mmol/l -6.7 mmol/l, and after two hours - up to 11.1 mmol/l, then we are talking about impaired glucose tolerance (prediabetes).

Diagnosis of diabetes is placed if a portion of blood on an empty stomach is determined more than 6.7 mmol/l glucose, and after two hours - over 11.1 mmol/l; or if during the first test the blood sugar level is more than 7 mmol/l.

What if the test results are bad?

If carbohydrate metabolism disorders are detected during a glucose tolerance test, the endocrinologist may prescribe repeat test or more complicated version with the use of corticosteroids. However, the technique is quite accurate, and the results can be erased only if the doctor’s instructions are not followed.

If the results are poor, the patient is referred for consultation to an endocrinologist, who will prescribe adequate treatment or correction of a prediabetic condition.

The glucose tolerance test is a multi-stage and rather complex, but quite informative research method. Most often, it is prescribed to persons at risk of diabetes mellitus or prediabetes (diagnosed disease in close relatives, obesity, pregnancy). " data-url="http://diabet-help.ru/kategoriya/diagnostika/glyukozotolerantnyij-test/" data-services="vkontakte,facebook,twitter,odnoklassniki,moimir,gplus">

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