What does serum insulin test check

Some patients often don't understand what the examinations and tests in the hospital are for, what they are checking, and what are the normal values ​​for the measured indicators? Especially as to what the serum insulin test is about, people are even more confused. In order to alleviate everyone's confusion, let's learn together the relevant knowledge about serum insulin test.

Serum insulin measurement

Insulin secretion can be affected by blood sugar levels. When blood sugar increases, insulin secretion increases; when blood sugar decreases, insulin secretion is inhibited. Blood sugar has a strong regulatory effect on insulin secretion.

【Reference value】

Radioimmunoassay: 35.88～208.1pmol/L (0.5～29μu/ml).

Clinical significance

Serum insulin levels are reduced in diabetic patients. In insulin-dependent diabetes (type I), the insulin content is absolutely reduced; in non-insulin-dependent diabetes (type II), the serum insulin level is not necessarily reduced, but it is because the number of insulin receptors on the cell membrane is reduced or the affinity with insulin is reduced. Decreased insulin secretion may also occur in pheochromocytomas because insulin secretion is inhibited by adrenaline secreted by the tumor cells.

Elevated serum insulin is seen in insulinomas and can cause hypoglycemia. It can also be seen in obese patients, who often have reduced glucose tolerance. Obese diabetic patients have higher plasma insulin levels due to their resistance to insulin. Elevated serum insulin can also be seen in chronic hepatitis. Judging from the delay in the peak of insulin release, the hyperinsulin release caused by chronic liver disease is due to the weakened responsiveness of pancreatic β cells to blood glucose; at the same time, high blood sugar can stimulate the secretion of certain gastrointestinal hormones, which can promote insulin secretion. Therefore, the above two factors prompt insulin secretion to exceed normal.

Since patients with diabetes and impaired glucose tolerance may have reduced insulin levels in their plasma, serum insulin measurement is of little significance for the diagnosis of diabetes. If the patient has used insulin (anti-insulin antibodies can be produced after 6 weeks of use), the radioimmunoassay method generally used in clinical practice will be seriously interfered with and affect the results, so it is even more worthless to measure.

Insulin function tests include:

C-peptide;Glycated hemoglobin;Hemoglobin A1C;

Serum glycosylated protein (GSP);

Insulin; proinsulin; glucagon, etc.