C‑Peptide Response to Glucose, 9 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 insulin) for evaluating glucose tolerance tests.
Special 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 (nine specimens). All tubes must be clearly marked with time drawn. Submit all tubes with one test requisition.
Limitations
Gross hemolysis is unacceptable. Plasma specimens are also rejected.
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 (preferred)
Minimum Volume
0.5 mL per specimen
Collection Instructions
Draw fasting specimen; administer glucose; collect each timed serum; clearly mark tubes with time drawn; submit with one requisition.
Patient Preparation
Patients should fast 12 hours prior to collection.
Causes for Rejection
Gross hemolysis; plasma specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 4 days |
| Refrigerated | 7 days |
| Frozen | Frozen –20 °C: 7 days; Frozen –70 °C: Not available |