C-Peptide

Message

SRHC Clients:

1 gold top tube or 1 red top tube
Patient must be fasting
Transport to SRHC laboratory within 8 hours

Test Code

LAB521

Quest Code

372

CPT Codes
84681

Preferred Specimen

1 mL serum (0.4 mL minimum)

Patient Preparation
Patients should fast 12 hours prior to collection

Minimum Volume

0.5 mL

Transport Container

Serum Separator tube or no additive red top

Transport Temperature

Room temperature

Specimen Stability

Room temperature: 4 days
Refrigerated: 7 days
Frozen: 7 days

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

Room temperature samples received more than 24 hours after collection

Methodology
Immunoassay (IA)

Setup Schedule

Set up: Mon-Sat; Report available: 1-2 days

Reference Range

0.80-3.85 ng/mL

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.

Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153

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.