BLOOD SUGAR TEST

What is the Glucose

Glucose is the most important component of blood, responsible for carbohydrate metabolism and serving as a vital nutrient for most cells, especially brain tissue.

More than half of the energy consumed by the human body is produced through the oxidation of glucose.

The concentration of glucose in the blood is regulated by hormones. Insulin is the main hormone produced by the pancreas. When insulin is deficient, blood glucose levels rise and body cells experience energy starvation.

A blood glucose test should be performed periodically by everyone. The World Health Organization (WHO) recommends testing every three years after the age of 40. People belonging to risk groups (overweight, family history of diabetes) should be tested annually. This helps to detect the disease in a timely manner and prevent complications.

There are several signs that may indicate elevated blood glucose levels:

• persistent thirst;
• increased urination;
• dry mouth;
• itching of the skin and mucous membranes (most commonly of the genital area);
• general weakness and fatigue;
• frequent boils.

If such symptoms are present, especially in combination, it is necessary to consult a physician or undergo a fasting finger-prick blood glucose test in the morning.

Normal Blood Glucose Levels

Fasting blood sample

• 3.5–5.7 mmol/L — normal range for adults;
• 4.2–6.4 mmol/L — normal range for children;
• In elderly individuals and during pregnancy, normal glucose levels range from 3.3–6.5 mmol/L.

Pregnancy may trigger the development of diabetes; therefore, pregnant women should monitor fluctuations in blood glucose levels by undergoing regular blood glucose testing.

Blood glucose testing should be performed while following a normal diet. No special dietary restrictions are required, and there is no need to avoid sweets; however, excessive food intake should be avoided on the day before testing. Testing should not be performed during acute conditions such as colds, trauma, or myocardial infarction.

Elevated Blood Glucose Levels (Hyperglycemia)

Hyperglycemia may be observed in the following conditions:

• diabetes mellitus;
• endocrine disorders;
• pancreatic diseases;
• chronic liver and kidney diseases;
• cerebral hemorrhage;
• myocardial infarction;
• use of certain medications (e.g., caffeine, estrogens, glucocorticoids).

Blood glucose levels may also increase after strong emotional stress, psychological stress, improper diet, and smoking.

Decreased Blood Glucose Levels (Hypoglycemia)

Hypoglycemia is characteristic of:

• pancreatic diseases (hyperplasia, adenoma, carcinoma);
• endocrine disorders (hypothyroidism, Addison’s disease);
• overdose of hypoglycemic drugs or insulin;
• severe liver diseases (cirrhosis, hepatitis, carcinoma);
• adrenal tumors, gastric cancer, fibrosarcoma;
• enzyme deficiencies, poisoning with arsenic or alcohol, and overdose of certain medications (antihistamines, anabolic steroids);
• intense physical exertion and febrile conditions.

Which Test Is More Accurate: Rapid Test or Laboratory Test?

In some medical centers, blood glucose testing is performed using a rapid method (glucometer). A glucometer is also convenient for home monitoring of blood glucose levels. However, rapid test results are considered preliminary and are less accurate than laboratory-based measurements. Therefore, if abnormal results are detected, laboratory testing is mandatory.

In the laboratory, a glucose tolerance test (GTT) may be performed to detect latent diabetes. First, fasting blood glucose is measured. Then the patient drinks 75 g of glucose in the form of a syrup, and the test is repeated after 2 hours.

Tests that need to be taken

Glucose (capillary blood)

Blood glucose (venous blood)

Blood glucose (glucometer)

Glycated hemoglobin (HbA1c)

Glucose tolerance test (three measurements)

Glucose tolerance test (abbreviated)