A C-Peptide test measures the level of C-peptide in the blood or urine. C-peptide is a byproduct produced in equal amounts to insulin when proinsulin is split into insulin and C-peptide in the pancreas. Since C-peptide is released alongside insulin, it serves as a reliable indirect measure of how much insulin the body is producing.
This test is primarily used to differentiate between Type 1 and Type 2 diabetes, assess residual insulin production in diabetic patients, evaluate hypoglycemia (low blood sugar), and detect insulin-secreting tumors (insulinomas). It is also used to monitor patients who have undergone pancreatic surgery or islet cell transplantation.
