C‑Peptide Response to Glucose, 5 Specimens
Use
C‑Peptide is useful in the evaluation of pancreatic beta cell function, such as distinguishing between type 1 and type 2 diabetes mellitus, monitoring patients post islet or pancreatic transplant, and identifying the source of insulin in hyperinsulinemic hypoglycemia (e.g., insulin‑secreting tumors vs exogenous insulin). It is also more hemolysis‑resistant than insulin itself and serves as an adjunct in glucose tolerance testing.
Special Instructions
Patients should fast for 12 hours prior to collection. After fasting specimen is drawn, administer oral glucose solution (1.75 g/kg body weight, maximum 75 g). Collect five timed serum specimens, each clearly labeled with time drawn. Submit all tubes with a single test requisition. Transport in transport tubes at room temperature.
Limitations
Not provided.
Methodology
Immunoassay
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
Container
transport tube(s)
Collection Instructions
Draw fasting specimen. Administer glucose. Collect 1 mL serum for each timed specimen post‑glucose dose. Tubes must be clearly marked with time drawn. Submit all tubes with one requisition.
Patient Preparation
Fast 12 hours prior to collection.
Causes for Rejection
Gross hemolysis • Plasma
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 4 days |
| Refrigerated | 7 days |
Other tests from different labs that may be relevant