C chain --> c-peptide
(Science: protein) c-peptide is a byproduct of normal insulin production by the beta cells in the pancreas. Normal values are 0.5 to 3.0 ng/ml. Normal levels indicate that the body is still producing its own insulin. Low levels indicate that the pancreas is producing little or no insulin. Elevations can be seen in cases of insulinomas and islet of langerhans tumours.