Official statistics on the incidence of diabetes can shock. Over the past decade, the number of patients suffering from this pathology has at least doubled. Almost the same number of people do not even know about their diagnosis, because in the initial stages, hyperglycemia can occur without pronounced symptoms, and the test results are normal. Glucose tolerance test is one of the universal diagnostic methods used for timely detection of the disease in all modern countries of the world.
Diabetes is an epidemic of the 21st 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 He alth 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 character of systemic vascular complications. In most patients, against the background of diabetes mellitus, nephropathy, retinopathy develops, the main vessels of the heart, brain, and peripheral vessels of the legs are affected. All these complications lead to disability of patients in eight cases out of ten, and in two of them - to death.
In this regard, the Federal State Budgetary Institution "Endocrinological Research Center of the Russian Academy of Medical Sciences" under the Ministry of He alth of Russia has improved the "Algorithms for specialized medical care for patients suffering from hyperglycemia." According to the results of control and epidemiological studies conducted by this organization for the period from 2002 to 2010, we can talk about the excess of the true number of patients suffering from this disease over the number of officially registered patients by four times. Thus, diabetes in Russia is confirmed in every fourteenth inhabitant.
The new edition of Algorithms emphasizes a personalized approach to setting therapeutic targets for carbohydrate metabolism and blood pressure control. The positions regarding the treatment of vascular complications of pathology were also revised, new provisions were introduced for the diagnosis of diabetes mellitus, including during the gestational period.
What is PGTT
Glucose tolerance test, the norms and indicators of which you will learn from this article, is a very common study. The principle of the laboratory method is to take a glucose-containing solution and monitor changes associated with the concentration of sugar in the blood. In addition to the oral method of application, the composition can also be administered intravenously. However, this method is used very rarely. The oral glucose tolerance test is being carried out everywhere.
How this analysis is carried out, almost every woman who was registered in the antenatal clinic for pregnancy knows. This laboratory method allows you to find out what level of glucose is in the blood before meals and after a sugar load. The essence of the procedure is to identify disorders associated with susceptibility to glucose entering the body. A positive glucose tolerance test does not mean that a person has diabetes. In some cases, the analysis allows us to draw a conclusion about the so-called pre-diabetes - a pathological condition that precedes the development of this dangerous chronic disease.
Lab test principle
As you know, insulin is a hormone that converts glucose that enters the bloodstream and transports it to every cell of the body in accordance with the energy needs of various internal organs. Insufficient insulin secretion is referred to as type 1 diabetes. If this hormone is produced in sufficient quantities, but at the same time its susceptibility to glucose is impaired, diabetes is diagnosed.second type. In both cases, passing a glucose tolerance test will determine the degree of overestimation of blood sugar values.
Indications for analysis appointment
Today, such a laboratory test can be taken in any medical institution due to the simplicity and general availability of the method. If an impaired glucose sensitivity is suspected, the patient receives a referral from a doctor and is sent for a glucose tolerance test. Wherever this study is conducted, in a public or private clinic, specialists use a single approach in the process of laboratory study of blood samples.
Sugar tolerance test is most often ordered to confirm or rule out prediabetes. A stress test is usually not necessary to make a diagnosis of diabetes mellitus. As a rule, a laboratory-recorded excess of glucose in the bloodstream is enough.
It is not uncommon for situations in which blood sugar levels remain in the normal range on an empty stomach, so the patient, taking routine blood sugar tests, always received satisfactory results. Glucose tolerance test, in contrast to conventional laboratory diagnostics, allows you to determine violations of insulin susceptibility to sugar just after saturation of the body. If the concentration of glucose in the blood is significantly higher than normal, but the tests performed on an empty stomach do not indicate a pathology, prediabetes is confirmed.
The doctors consider the following grounds for conducting OGTTcircumstances:
- the presence of symptoms of diabetes mellitus with normal values of laboratory tests, that is, the diagnosis was not previously confirmed;
- genetic predisposition (in most cases, diabetes is inherited by a child from mother, father, grandparents);
- exceeding the norm of sugar 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 he althy person;
- obesity and overweight.
In other situations, a glucose tolerance test may also be considered. What else can be indications for this analysis? First of all, pregnancy. The study is performed in the second trimester, regardless of whether fasting glucose levels are overestimated or are within the normal range - all expectant mothers pass the glucose sensitivity test without exception.
Glucose tolerance in children
At an early age, patients with a predisposition to the disease are referred for research. Periodically, a child who was born with a large weight (more than 4 kg) and, as he grows up, also has overweight, will have to take an analysis. 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 tolerance test, which will be discussed later, therefore, such an analysis is not done without special need.
How the procedure goes
This laboratory analysis is performed exclusively in stationary conditions under the supervision of medical staff. Here is how the glucose tolerance test is done:
- In the morning, strictly on an empty stomach, the patient donates blood from a vein. The concentration of sugar in it is urgently determined. If it does not exceed the norm, proceed to the next stage.
- The patient is given a sweet syrup to drink. It is prepared as follows: 75 g of sugar is added to 300 ml of water. For children, the amount of glucose in the solution is determined at the rate of 1.75 g per 1 kg of weight.
- A couple of hours after the administration of the syrup, venous blood is re-sampled.
- The dynamics of changes in the level of glycemia is assessed and the results of the test are given.
To avoid errors and inaccuracies, the sugar level is determined immediately after blood sampling. Prolonged transport or freezing is not allowed.
Preparing for analysis
As such, there are no specific measures to prepare for a glucose tolerance test, with the exception of the obligatory condition to donate blood on an empty stomach. It is impossible to influence the parameters of blood taken again after taking glucose - they depend only on the correct administration of the solution and the accuracy of laboratory equipment. At the same time, the patient always has the opportunity to influence the result of the first test and prevent the test from being unreliable. Several factors can distort the results:
- drinking alcohol the night beforeresearch;
- digestion disorder;
- thirst and dehydration, especially in hot weather with insufficient water intake;
- exhausting physical work or intense exercise on the eve of the analysis;
- drastic changes in nutrition associated with the rejection of carbohydrates, starvation;
- smoking;
- stress situations;
- a catarrhal disease transferred a few days before the test;
- recovery postoperative period;
- restriction of motor activity, bed rest.
It is important to pay special attention to preparing for the glucose tolerance test. Normally, the patient should inform the doctor about everything that may affect the result of the test.
Contraindications for testing
This test is not always safe for patients. The study is terminated if, during the first blood sampling, which is carried out on an empty stomach, glycemic indicators exceed the norm. A glucose tolerance test is not carried out even if preliminary urine and blood tests for sugar have exceeded the threshold of 11.1 mmol / l, which directly indicates diabetes. The sugar load in this case can become very dangerous for he alth: after drinking sweet syrup, the patient may lose consciousness or even fall into a hyperglycemic coma.
Contraindications for a glucose sensitivity test are:
- acute infectious or inflammatorydiseases;
- third trimet of pregnancy;
- Children under 14;
- acute form of pancreatitis;
- presence of diseases of the endocrine system, which are characterized by high blood sugar levels: Itsenko-Cushing's syndrome, pheochromocytoma, hyperthyroidism, acromegaly;
- taking strong drugs that can distort the results of the study (hormonal drugs, diuretics, antiepileptics, etc.).
Despite the fact that today you can buy an inexpensive glucometer at any pharmacy, and the glucose solution for a glucose tolerance test can be diluted at home, it is forbidden to conduct a study on your own:
- Firstly, not knowing about the presence of diabetes, the patient runs the risk of seriously worsening his condition.
- Secondly, accurate results can only be obtained in laboratory conditions.
- Thirdly, it is undesirable to take such a test often, since it is a huge burden for the pancreas.
The accuracy of portable devices sold in pharmacies is not enough for this analysis. Such devices can be used to determine the level of glycemia on an empty stomach or after a natural load on the gland - a normal meal. With the help of such devices it is very convenient to identify products that significantly affect the concentration of glucose. Based on the information received, you can create a personal diet to prevent or control diabetes.
Transcript of test results
The receivedresults compared to normal values, which are confirmed in he althy people. If the received data exceeds the established range, the specialists make the appropriate diagnosis.
For morning blood sampling taken from a patient on an empty stomach, the norm is less than 6.1 mmol/l. If the indicator does not go beyond 6.1-7.0 mmol / l, they speak of prediabetes. In the case of obtaining results exceeding 7 mmol / l, there is no doubt that the person has diabetes mellitus. The second part of the test is not performed 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 confirmation of diabetes, and pre-diabetes is diagnosed with a value between 7.8 and 11.1 mmol/L.
The oral glucose tolerance test is a comprehensive laboratory test that measures the response of the pancreas 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 overestimated, but also underestimated.
If blood sugar is below normal levels, this phenomenon is called hypoglycemia. If it is present, the doctor can make an assumption about diseases such as pancreatitis, hypothyroidism, liver pathology. Blood glucose is below normalbe the result of alcohol, food or drug poisoning, the use of arsenic. Sometimes hypoglycemia is accompanied by iron deficiency anemia. In any case, with low values of the glucose tolerance test, we can talk about the need for additional diagnostic procedures.
In addition to diabetes and pre-diabetes, an increase in glycemia may also indicate disorders in the endocrine system, cirrhosis of the liver, diseases of the kidneys and the vascular system.
Why do a glucose tolerance test for pregnant women
Laboratory testing of blood with a sugar load is an important diagnostic measure for every expectant mother. Excess glucose can be a sign of gestational diabetes. This pathology can be temporary and disappear after childbirth without any intervention.
In antenatal clinics and gynecological departments of Russian medical institutions, this type of study is mandatory for patients registered for pregnancy. For the delivery of this analysis, the recommended terms are established: a glucose tolerance test is carried out in the period from 22 to 28 weeks.
Many pregnant women wonder why they even need this test. The thing is that during the gestation of the fetus, serious changes occur in the body of women, the work of the endocrine glands is rebuilt, the hormonal background changes. All this can lead to insufficient production of insulin or a change in its susceptibility to glucose. This is the main reason whypregnant women are at risk for developing diabetes.
In addition, gestational diabetes is a threat not only to the he alth of the mother, but also her unborn baby, since excess sugar will inevitably enter the body of the fetus. A constant excess of glucose will lead to weight gain for mother and child. A large fetus, whose body weight exceeds 4-4.5 kg, will experience more stress when passing through the birth canal, may suffer from asphyxia, which is fraught with the development of CNS complications. In addition, the birth of a baby with such a weight is also a huge risk to a woman's he alth. In some cases, gestational diabetes has been the cause of premature delivery or miscarriage.
How to take a glucose tolerance test for pregnant women? Fundamentally, the research methodology does not differ from that described above. The only difference is that the expectant mother will have to donate blood three times: on an empty stomach, an hour after the injection of the solution and two hours later. In addition, capillary blood is taken before the test, and venous blood is taken after taking the solution.
Deciphering the values in the laboratory report looks like this:
- Fasting test. Values less than 5.1 mmol/l are considered normal, gestational diabetes is diagnosed at 5.1-7.0 mmol/l.
- 1 hour after taking the syrup. A normal glucose tolerance test result for pregnant women is less than 10.0 mmol/L.
- 2 hours after taking glucose. Diabetes is confirmed at values of 8.5-11.1mmol/l. If the result is less than 8.5 mmol/L, the woman is he althy.
What to pay special attention to, reviews
Glucose tolerance test with high accuracy can be taken in any budget hospital under the compulsory he alth insurance policy for free. If you believe the feedback from patients who have tried to independently determine the level of glycemia with a glucose load, portable glucometers are not able to give reliable results, so laboratory results can be completely different from those obtained at home. If you are going to donate blood for glucose tolerance, you need to consider a number of important points:
- You need to take the analysis strictly on an empty stomach, because after eating sugar is absorbed much faster, and this leads to a decrease in its level and obtaining unreliable results. The last meal is allowed 10 hours before the analysis.
- There is no need to perform a laboratory test without special need - this test is a difficult load on the pancreas.
- After a glucose tolerance test, you may feel a little sick - this is confirmed by numerous patient reviews. You can conduct a study only against the background of normal he alth.
Some experts do not recommend chewing gum or even brushing your teeth with toothpaste before the test, as these oral care products may contain sugar, albeit in small quantities. Glucose begins to be immediately absorbed in the oral cavity,therefore, the results may be false positive. Certain medications can affect the concentration of sugar in the blood, so it is better to stop using them a few days before the analysis.
