C-Peptide Response to Glucose, 7 Specimens

Test Code

15847

CPT Codes
84681 (x7)

Preferred Specimen

1 mL serum per specimen

Patient Preparation
Patients should fast 12 hours prior to collection

Minimum Volume

0.5 mL per specimen

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. All tubes must be clearly marked with time drawn. Submit all tubes with one test requisition.
Reference ranges available: Fasting, 30, 60, 90, 120, 150, 180, 240 and 300 minutes post glucose.

Transport Temperature

Room temperature

Specimen Stability

Room temperature: 4 days
Refrigerated: 7 days
Frozen -20° C: 7 days
Frozen -70° C: Not available

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Gross hemolysis • Plasma

Methodology
Immunoassay (IA)

Setup Schedule

P.M.

Clinical Significance

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.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.