How to check growth hormone?

Parents are very concerned about their children's growth and hope that their children can grow taller. There are many factors that affect children's growth, such as a close relationship with genes, and also closely related to children's daily diet and exercise. In the process of children's physical growth, a hormone in the body plays an important promoting role, that is, growth hormone. How is growth hormone checked clinically?

How to check growth hormone?

Determination of GH deficiency. Although the micro-assay technology has been updated from the original radioimmunoassay to the current immunoradiometric analysis, and the sensitivity has been increased by several orders of magnitude, it still cannot distinguish between the lower limit of normal in bleeding and the GH level in pituitary GH deficiency dwarfism. This may be related to the very low basal value of GH in normal human blood. Therefore, to determine the level of GH, it is necessary to check it under specific circumstances and combine multiple tests to make a judgment. Commonly used tests include:

1. Draw blood 30 to 60 minutes after falling asleep and detect the GH concentration at the physiological GH peak.

2. Collecting urine from 9 pm to 7 am the next morning and measuring the GH excreted in the urine also has a certain reference value and may be able to distinguish the lower limit of normal; its practice is still limited and needs further observation and summary.

3. Arginine stimulation test: Arginine is injected intravenously after fasting overnight, at a dose of 0.5 g/kg, up to 20 g, over 30 minutes. Blood is drawn before the test and 15, 30, 90, and 120 minutes after the test to measure the GH concentration. When stimulated by this, normal people will experience a peak in GH secretion within 30 to 90 minutes. In pituitary GH deficiency dwarfism, there is no GH release peak or the peak is low.

4. Levodopa stimulation test Levodopa is taken orally, 125 mg when the body weight is 15 kg, 250 mg when the body weight is between 15 and 35 kg, and 500 mg when the body weight is greater than 35 kg. Blood is drawn before and after taking the medicine. Its clinical significance is the same as that of the arginine stimulation test. The main side effects are gastrointestinal discomfort such as nausea.

5. Clonidine stimulation test Clonidine is taken orally, 0.10-0.15 mg/m2, and blood is drawn and its clinical significance is similar to that of the arginine stimulation test. Note that a small number of patients may experience hypotension and drowsiness.

6. Insulin hypoglycemia test Hypoglycemia is a serious stress condition for the human body, during which a large amount of GH will be released in the body. This test involves certain risks and discomfort. Generally, 0.075-0.1U/kg of human insulin is used, dissolved in normal saline and injected within 2 minutes. The blood sugar level is required to be lower than 2.5mmol/L (45mg/dl) or 50% of the original level within the next 20-40 minutes. After the peak of hypoglycemia, GH generally increases, and cortisol also increases. To prevent hypoglycemia coma and convulsions, intravenous saline drip should be opened and glucose injection should be prepared.

All of the above tests have false positives and false negatives, but the insulin hypoglycemia test has the least. In clinical practice, judgments are often made in combination with the other three tests. If the results are still ambiguous, a hypoglycemia stimulation test is added. Other tests include glucagon, vasopressin, etc., which are rarely used clinically.