C-Peptide Response to Glucose, 3 Specimens
Use
C‑Peptide is useful in the evaluation of pancreatic beta cell function (e.g., helping distinguish type 1 from type 2 diabetes mellitus, or monitoring patients who have received islet cell or pancreatic transplants) and for determining the source of insulin in patients with hyperinsulinemic hypoglycemia (e.g., distinguishing insulin‑secreting tumors from exogenous insulin administration). It is also sometimes measured as an additional means (more resistant to hemolysis than is insulin itself) for evaluating glucose tolerance tests.
Special Instructions
Patient should fast for 12 hours prior to collection. Draw fasting specimen, administer oral glucose solution (1.75 g/kg body weight or 75 g maximum), then collect timed specimens post‑glucose dose. Tubes must be clearly marked with time drawn and submitted together with one test requisition.
Limitations
Not provided.
Methodology
Immunoassay (Other)
Biomarkers
Result Turnaround Time
Not provided.
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL per specimen
Minimum Volume
0.5 mL per specimen
Collection Instructions
Draw fasting specimen. Administer oral glucose solution (1.75 g/kg body weight or 75 g maximum). Collect 1 mL serum for each timed specimen post glucose dose. Tubes must be clearly marked with time drawn.
Patient Preparation
Fasting 12 hours prior to collection
Causes for Rejection
Gross hemolysis • Plasma
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 4 days |
| Refrigerated | 7 days |
| Frozen | Frozen ‑20 °C: 7 days; Frozen ‑70 °C: Not available |