Explore this test
- Test Details
- Lab Values
- Clinical Significance
- Treatment Options
Connecting Peptide (C-peptide) is a polypeptide produced by β-cells of the pancreas along with insulin. It serves as an accurate measure of insulin production, even in patients receiving insulin treatment.
1.0 mL serum (0.5 mL minimum) collected in serum separator tube (SST / Tiger Top)
1.0 mL (minimum) plasma collected in EDTA plasma separator tube (Pearl Top)
Refrigerated (ship on frozen cold packs)
Refrigerated: 3 days
- Optimal: <3.0 ng/mL
- Borderline: 3.0 – 4.0 ng/mL
- Increased Risk: >4.0 ng/mL
- Borderline: 2.0 – 4.0 ng/mL
- Increased Risk: <2.0 or >4.0 ng/mL
Elevated C-peptide levels associated with:
- insulin resistance
- renal insufficiency
Decreased C-peptide levels associated with:
- insulin deficiency
- Addison’s disease
- post pancreatectomy
- High doses of biotin (> 5 mg/day) may interfere with assay results. Patient assumed to be refraining from biotin supplementation for at least 3 days prior to blood draw.
- Insulin treatment for diabetic patients with low levels.
- Lifestyle modification and other agents for diabetic patients with normal or elevated levels.