Glucose in urine / 24h (daily urine), quantitatively
Why this test?
- To detect diabetes.
- To control the course of diabetes.
- To evaluate the effectiveness of diabetes treatment.
- To assess kidney function.
- To evaluate the functioning of the endocrine system (pancreas, thyroid gland, pituitary gland, adrenal glands).
- To monitor the condition of a pregnant woman.
In what cases is it prescribed?
- If diabetes is suspected.
- When it is necessary to evaluate the course of diabetes and the effectiveness of its treatment.
- If renal dysfunction is suspected If there were cases of tubulopathies in the family.
- In case of suspicion of endocrine disorders in the body (hyperthyroidism, Itsenko-Cushing's syndrome and disease, pheochromocytoma, acromegaly).
- During pregnancy, especially in the late stages.
Glucose belongs to the class of carbohydrates (sugars) and serves as a universal source of energy in the body. Its name comes from the Greek word glykys - "sweet".
Glucose is a monomer, in nature and in humans it is found both in the composition of polymers and separately. The main role of glucose in the body is energetic - participation in biochemical reactions that provide the cells of the body with energy - it also performs a structural function, being a part of various molecules.
Carbohydrates enter the body with food. Their share with a balanced diet accounts for 75% of the volume and 50% of the caloric content of the daily diet. Food carbohydrates are represented by starch (a polymer of glucose contained in plant food), glycogen (a polymer of glucose contained in animal food), sucrose (a dimer consisting of fructose and sucrose), monosugars (lactose of milk, fructose and glucose of honey and fruit ).
Carbohydrates can be formed from lipids and amino acids, but this process leads to the appearance of ketone bodies and nitrogenous products, which in large quantities and with prolonged action have an adverse effect on the state of the body. The liver also contains a reserve of glycogen. In the mouth and intestines, sugars are broken down, absorbed and then enter the blood.
The concentration of glucose in the blood is maintained at a constant level by the interaction of hormones. Both an increase and a decrease in blood glucose are dangerous - hyper- and hypoglycemic coma is possible. In the kidneys, glucose enters the primary urine, which is formed when blood passes through the cortical substance of the kidneys (renal glomeruli). In the medulla of the kidney (tubular part), there is almost a complete transition of glucose from the primary urine into the blood (reabsorption), provided that the blood glucose level is below a certain threshold. Glucose does not enter the urine.
There are two main factors that determine the appearance of glucose in the urine: an increase in blood glucose above the renal threshold (hyperglycemia) and impaired reabsorption of glucose in the kidneys due to their damage. Maybe a combination of these reasons. In kidney diseases that disrupt the work of the nephron, there is incomplete reabsorption of glucose and it appears in the urine. There is a primary damage to the tubules (tubulopathy) - a rare hereditary disease in which the ability to reabsorb certain substances in the renal tubules suffers (de Toni - Debret - Fanconi syndrome, primary glucosuria), and a secondary damage, when the function of the kidneys as a whole is disturbed (glomerulonephritis, renal deficiency, poisoning).
Glucosuria associated with the work of the kidneys can be detected in pregnant women, especially in the later stages. In this case, to prevent complications, it is necessary to be under the supervision of a doctor. An increase in the content of glucose in the blood leads to its increase in primary urine, when a certain threshold is exceeded, even healthy kidneys do not completely reabsorb glucose, so that it enters the urine.
Blood glucose can increase in healthy people with excessive consumption of carbohydrates in food, stress, occasional use of certain medications. In general, the level of blood glucose depends on hormonal regulation, and its fluctuations indicate a pathology of the endocrine system. Hormones affecting the metabolism of carbohydrates are usually divided into insulin and counterinsular hormones.
The action of insulin is aimed at reducing the level of glucose in the blood: it promotes the transition of glucose into tissues, stimulates the synthesis of glycogen and inhibits its breakdown into glucose, inhibits the formation of glucose from amino acids and lipids.
Insulin is synthesized by endocrine cells of the pancreas. In diabetes, the synthesis of insulin (insulin-dependent diabetes) or the reaction of the body's cells to it (non-insulin-dependent diabetes) is impaired, and when the pancreas is removed or significantly damaged in pancreatitis, insulin deficiency also develops. This leads to an increase in glucose in the blood and the appearance of glucose in the urine. In the treatment of diabetes, a stable blood glucose level is achieved, and glucosuria can be a signal to correct therapy.
Contrainsular hormones are glucagon of the pancreas, cortisol of the cortical substance of the adrenal glands, adrenaline of the medulla of the adrenal glands, somatotropin of the anterior lobe of the pituitary gland, and thyroid hormones. Their action has a number of features, but in general, as far as glucose metabolism is concerned, it is the opposite of insulin: stimulation of the breakdown of glycogen and insulin, glucose is synthesized from lipids and amino acids, and its level in the blood increases.
The action of counterinsular hormones is aimed at meeting energy needs during periods of stress and muscle tension. An increase in the level of counterinsular hormones leads to hyperglycemia and the appearance of glucose in the urine. This happens with long-term use of the corresponding drugs (glucocorticoids, thyroid hormones, somatotropic hormone), with hormone-producing tumors of the thyroid gland, adrenal glands, pancreas, and pituitary gland.