Tests That Diagnose Diabetes

Confirmation of diabetes is carried out based on the evaluation of the results of several laboratory tests that assess the amount of circulating glucose in the blood: the fasting glucose test, capillary blood glucose test, glucose tolerance test, and glycosylated hemoglobin test.

Tests that assess the amount of glucose in the blood are requested by the doctor when the person has a family member with diabetes or when they have characteristic symptoms of the disease, such as constant thirst, constant urination or weight loss for no apparent reason, for example. However, these tests can be requested without suspicion of diabetes risk, only for the doctor to assess the general state of health of the person. Know all the symptoms of diabetes.

Normal blood glucose values vary according to the type of test and may also vary according to the laboratory due to the technique used to analyze. In general, the test values   for diabetes are indicated in the following table:

It is important to remember that the blood test is the main one used to confirm the diagnosis of the disease. Normally the doctor usually repeats the test when there is an alteration to confirm the diagnosis. In cases where the value indicates prediabetes, it means that the patient has a high risk of developing the disease, however, it is possible to follow a series of recommendations to prevent this from happening

Fasting Glucose Test

The fasting glucose test is the blood test that is performed conventionally, which measures the amount of blood sugar during a given time, and must be performed after fasting for at least 8 hours. In case the value is above normal, the doctor may request other tests, mainly glycosylated hemoglobin, which indicates the average amount of glucose in the 3 months prior to the completion of this test. In this way, the doctor can assess whether the person is at risk or suffers from the disease.

If the result obtained indicates a risk of diabetes, it is necessary to make changes in lifestyle such as dietary modifications and physical activity, to prevent the onset of the disease. However, when the diagnosis of the disease is confirmed, in addition to changes in lifestyle, it is also necessary to take medications and, in some cases, the doctor may indicate insulin injections.

Glucose Tolerance Test

The glucose tolerance test, also known as the glucose tolerance curve is performed with the objective of evaluating the functioning of the organism against various glucose concentrations. For this, 3 blood glucose measurements are made: the first is done on an empty stomach, the second 1 hour after the ingestion of the sugary drink, which is usually a sugar syrup, and the third 2 hours after the first measurement.

In some cases, 4 blood measurements can be performed until 2 hours after the ingestion of the drink is completed, with measurements taken 30, 60, 90 and 120 minutes after the consumption of sugar syrup.

This test helps to diagnose diabetes, prediabetes, insulin resistance, and pancreatic alterations and is frequently requested in the investigation of gestational diabetes.

Capillary Blood Glucose Test

The capillary blood glucose test is performed using a device called a glucometer, which measures the amount of blood sugar instantly, without the need for the person to go to a laboratory. This test is very easy to do, this device brings a lancet that contains a sterilized needle, which must be changed every time it is used, with which the finger is punctured and when a drop of blood comes out it must be collected with the groove of the test strip that the glucometer is inserted.

It is not necessary to fast for this test since the result is positive for diabetes if it is greater than 200 mg / dL, and must be confirmed by a blood test. However, this test is also used for diabetics to keep their blood glucose levels controlled both on an empty stomach and after meals. This device can be purchased at pharmacies, online stores and there are even some health systems that offer it for free.

Glycosylated Hemoglobin Test

The glycosylated hemoglobin or HbA1c test is performed from the fasting normal blood test and indicates the amount of sugar attached to the red blood cells during the last 3 months. This is because the circulating glucose in the blood binds to hemoglobin and stays together until the erythrocyte's lifetime ends, which is 10 days.

So its result indicates how the control of the disease has been at both the diet and treatment level during the last 90 days, showing if there was improvement or if the disease worsened, and the greater its value, the greater its severity and the risk of complications.

Who Should Take These Exams?

It is advised that all people who present risk factors or who have symptoms of diabetes, should be tested to confirm the disease. It is also important that pregnant women do it to prevent complications related to excess blood sugar during pregnancy.

In addition to this, people who are losing a lot of weight for no apparent reason, especially children and adolescents, also need to have blood glucose tests to diagnose the possibility of type 1 diabetes.

Finally, it is important to remember that all diabetics should have regular exams to have better control of the disease.