How does a person know about his diagnosis? First, he notices persistent thirst and dry mouth, then he pays attention to constant fatigue and malaise, and when even his favorite jeans without a belt fly off, this becomes a serious cause for concern, and the person goes to the doctor.
Yes, the symptoms are usually the same, but they are not enough to make a diagnosis. Analysis is indispensable here.
Methods for diagnosing type 1 diabetes
– Directly for the diagnosis of type 1 diabetes, the following are used: measurement of glycemia of venous and whole capillary blood (on an empty stomach and two hours after a glucose tolerance test, as well as random determination of glycemia during the day with symptoms of high blood sugar) and an assessment of the level of glycated hemoglobin, – says endocrinologist, Ph.D. Nadezhda Lebedeva. – However, the oral glucose tolerance test (OGTT) in the diagnosis of type 1 diabetes is used less frequently, because the disease usually manifests with high glycemic values and OGTT is often simply not required.
But this is not all that is available in the arsenal of doctors. Specialists also use indirect methods: measuring ketone bodies and glucose in the urine, assessing the level of C-peptide. These methods, according to our expert, help to suspect diabetes and assess the situation, but it is not possible to make a diagnosis. Since, for example, ketone bodies in the urine can be detected due to the fact that a person is on a diet, and diabetes mellitus has nothing to do with it.
And in order to determine that we are dealing with type 1 diabetes mellitus, and not some other diabetes, in doubtful cases, a study of C-peptide, insulin and insulin resistance indices, antibodies to insulin, glutamate decarboxylase, pancreatic beta cells, zinc transporter is used 8, tyrosine phosphatase.
If you have read the previous sentence to the end, it is already good, but, you know, it is better to entrust the diagnosis to a professional. However, it does not hurt to have general information. Next, we will analyze each method in a little more detail.
Determination of the level of glycemia on an empty stomach
This method is the most important in the diagnosis of type 1 diabetes. Moreover, it, like the other methods described below, is also used when type 2 diabetes is suspected.
From the point of view of the patient, everything is simple: you need to donate blood on an empty stomach. Everyone has been tested at least once in their life, but few people know that “on an empty stomach” means not eating at least 8 hours before donating blood, and not just coming to the clinic in the morning without breakfast.
By the way, only this method is enough to establish a diagnosis. If glycemic values are high (11,1 mmol/l and above), and in addition there is a whole list of symptoms of type 1 diabetes, then the diagnosis of type 1 diabetes can be made by one digit of glycemia.
Analysis for glycated hemoglobin
There is no need to fast before donating blood. The fact is that using this method, the level of glucose in the blood over the past three months is analyzed. By the way, this figure is not taken from the ceiling – erythrocytes live for about 120 days.
“The glycated hemoglobin indicator reflects the average level of glycemia over the past three months, it is for this reason that it can be taken not on an empty stomach,” explains Nadezhda Lebedeva. – The level of glycated hemoglobin from 6,5% and one diabetic glycemia indicator allows diagnosing diabetes mellitus in a patient.
There are some other important points. So, according to the doctor, with the rapid development of the disease – as often happens – the level of HbA1c (glycated hemoglobin) may not be significantly increased, therefore, when making a diagnosis, one should focus on the clinic and glycemic indicators.
In addition, other factors can affect this indicator: anemia, pregnancy, a recent blood transfusion, and more – all this must be taken into account when assessing the indicator.
Oral glucose tolerance test
Such an analysis is done with dubious glycemia values uXNUMXbuXNUMXb- in order to clarify the diagnosis for sure. And in this case, the patient already needs to prepare.
– Three days before the analysis, the patient does not restrict himself in nutrition (more than 150 g of carbohydrates per day), but immediately before the test, you can’t eat anything for 8-14 hours, you can only drink water. The last evening meal should contain 30-50 g of carbohydrates, says the endocrinologist. – The test is carried out in the morning. After blood sampling on an empty stomach, the patient is given to drink 75 g of anhydrous glucose or 82,5 g of glucose monohydrate dissolved in 200-300 ml of water. Children are given 1,75 g of anhydrous glucose (or 1,925 g of glucose monohydrate) per kg of body weight as a load, but not more than 75 g (82,5 g). You need to drink a glucose solution no more than 5 minutes. After – you can not eat, drink, smoke and move actively for two hours. And then they take a second blood sample from a vein.
It should be noted that the diagnostic criteria for diabetes 2 hours after OGTT or during the day are indicators from 11,1 mmol/l and above.
Other methods
So, if the doctor has a young patient with symptoms typical of type 1 diabetes, plus hyperglycemia (high blood sugar), which was preceded by severe stress or SARS, then usually diagnosing type 1 diabetes is not difficult. But it happens that this is not enough.
“For the differential diagnosis of type 1 diabetes with other types of diabetes, additional examinations may be needed,” notes Dr. Lebedeva. – For example, a blood test for C-peptide is a fragment of proinsulin (its precursor), in type 1 diabetes this indicator is reduced, which reflects the absolute insufficiency of insulin. For differential diagnosis with DM2, it may be necessary to assess the level of insulin and calculate insulin resistance indices (in patients with overweight and obesity) – there is no insulin resistance in DM1. And in order to distinguish type 1 diabetes mellitus from LADA-diabetes, antibodies to insulin, glutamate decarboxylase, pancreatic beta cells, zinc transporter 8, tyrosine phosphatase are examined.
Popular questions and answers
How is type 1 diabetes diagnosed in newborns if both parents have this diagnosis?
Is it possible to predict DM1, “diagnose ahead of time”?
T1DM refers to an autoimmune disease in which the body’s defense cells, which are normally produced against foreign agents, begin to attack its own organs and tissues, in this case, the pancreas. To eliminate these cells so that the disease does not develop, modern medicine cannot yet. Research is being carried out in this direction. You can only treat the consequence of an antibody attack – insulin deficiency – by introducing insulin into the body from the outside. Therefore, blood glucose monitoring makes much more practical sense.
What is the probability of misdiagnosis when using these methods and what is the risk?
Another important point: the measurement of glycemia for diagnosis is not carried out against the background of short-term use of drugs that increase the level of glycemia (primarily glucocorticoids), as well as during acute diseases or exacerbation of chronic processes, because a person may experience a stressful increase in glucose. We definitely recommend re-testing for glycemia after treatment.