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Oxford University Hospitals NHS Foundation Trust
Clinical Biochemistry

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Specimen requirements

Sample type: Serum (Serum)

Collection requirements: Specimen should to be received and processed within 48 hours of collection.

Results on specimens received more than 48 hours after collection should be interpreted with caution.


Price on application

Turnaround time

Please see Turnaround times

Analytical method


Analysis undertaken at these site(s)

John Radcliffe Hospital

Reference intervals

A fasting C-peptide of <80 pmol/L or a stimulated C-peptide of <200 pmol/L suggests absolute insulin deficiency.

In insulin-treated diabetic patients, a stimulated C-peptide of <600 pmol/L suggests marked insulin deficiency and type1 DM.

C-peptide values close to thresholds should be interpreted with great caution and may not assist clinical decision.

C-peptide increases and is uninterpretable in renal impairment.