Accessibility links
|
|
C-Peptide
minimum sample volume required ~ 4ml
Test Code: CPE
Tube type: EDTA
Special instructions
Send separate Glucose (fluoride) sample.
Sample must be received in lab within 24 hours of collection.
Sent away
to Bristol Royal Infirmary
Reference range
240 - 1500 (In fasted but not hypoglycaemic individuals)
Units
pmol/L
Linked to
Insulin
Turnaround Time
7
days
Department: Biochemistry
Clinical Application
C-peptide is part of proinsulin and is cleaved before co-secretion with insulin by pancreatic beta cells. It is produced in equimolar concentrations to endogenous insulin and is used to assess the function of beta cells. Discrepancy between c-peptide and insulin measurements can help in the differential diagnosis of hypoglycaemia.
C-peptide may also be measured when querying if the patient is a type 1 or 2
diabetic.
Interpretation of random / post prandial C-peptide for investigation of patients with established diabetes mellitus (>3 years since onset):
Values greater than 300 pmol/L indicate substantial insulin secretion and is associated with type 2 DM, MODY and absence of absolute insulin requirement.
Values between 100 and 300 pmol/L indicate intermediate insulin secretion.
Values less than 100 pmol/L indicate severe insulin deficiency and individuals should be managed as type 1 DM.
During a hypoglycaemic episode (glucose ≤2.6 mmol/L), a C-peptide concentration of:
Greater than 150 pmol/L is inappropriately raised and is highly suggestive of hyperinsulinism.
50 – 150 pmol/L is considered indeterminate and requires measurement of beta-hydroxybutyrate to determine if hyperinsulinism is present.
Less than 50 pmol/L suggests appropriate suppression.
Webpage updated: July 2024.
