Test Code 410
Test Details
C-Peptide
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.
Methodology
Chemiluminescence
Patient Preparation
None
Preferred Specimen
Red & Yellow Top Tube
(CAT serum separator clot activator with gel)
Alternate Specimen
Transport Temperature
Refrigerated (ship on frozen cold packs)
Stability
Refrigerated: 7 days
Lab Values
C-Peptide
Non-Diabetic
- Optimal: <3.0 ng/mL
- Borderline: 3.0 – 4.0 ng/mL
- Increased Risk: >4.0 ng/mL
Diabetic
- Borderline: 2.0 – 4.0 ng/mL
- Increased Risk: <2.0 or >4.0 ng/mL
Clinical Significance
C-Peptide
Elevated C-peptide levels associated with:
- hyperinsulinemia
- insulin resistance
- obesity
- renal insufficiency
Decreased C-peptide levels associated with:
- insulin deficiency
- starvation
- hypoglycemia
- 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.
Treatment Options
C-Peptide
- Insulin treatment for diabetic patients with low levels.
- Lifestyle modification and other agents for diabetic patients with normal or elevated levels.
