C-Peptide, Serum/Plasma

C-peptide has an essential function in the synthesis of insulin. It links the A and B chains of insulin allowing correct folding and inter-chain disulphide bond formation. The proteolytic cleavage of C-peptide from proinsulin frees insulin’s B-chain to assume an appropriate conformation for effective interaction with the insulin receptor. When C-peptide is cleaved from proinsulin, it is stored in secretory granules, and eventually released into the bloodstream in amounts equimolar with those of insulin. Recent evidence suggests that C-peptide may stimulate specific intracellular processes, influencing renal and nerve function in C-peptide-deficient type 1 diabetes patients.

Measurement of C-peptide allows assessment of insulin secretion in insulin treated patients. Raised C-peptide levels are found in hypoglycaemia associated with insulinomas (small insulinsecreting tumours) and sulphonylurea misuse.

1 ml Serum 1 ml K3-EDTA or Li-Heparin Plasma Stability: 4 Hours at 15-25 °C 24 Hours at 2-8 °C 30 Days at -20 °C

State glucose level at the time of sample collection. Patient should be fasting. Freeze only once.

1.1-4.4 ng/mL