C-peptide

DESCRIPTION:
By splitting and separating the active form of insulin, the last product is C-peptide. C-peptide fulfills an important role in linking the structure of double-chain insulin. Insulin and C-peptide are secreted into the blood in equal amounts. Since half of insulin and almost none of C-peptide is separated in the liver, C-peptide has a longer half-life (about 35 min) than insulin, so there is 5 to 10 times more concentration of C-peptide in the peripheral circulation and therefore these levels vary much less. Before blood collection, you must be fasting, unless the doctor asks otherwise.

CLINICAL SIGNIFICANCE:
Determination of C-peptide, insulin and glucose is used in the differential diagnosis of hypoglycemia in order to determine the adequate therapy of the patient. Also, the determination of C-peptide can help in determining the remaining function of ß-cells in the early phase of type-1 diabetes mellitus and for the differential diagnosis of late autoimmune diabetes in adults and in type-2 diabetes. Because C-peptide is excreted by the kidneys, elevated levels of C-peptide can be found in kidney disease. Elevated levels of C-peptide can occur due to increased activity of ß-cells and are also observed in hyperinsulinism due to renal insufficiency or obesity. REDUCED levels of C-peptide have been observed in fasting, hypoglycemia, hypoinsulinism, Addison’s disease, and after radical pancreatectomy.