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HelpTest Code CPEP C-Peptide, Serum
Reporting Name
C-Peptide, SUseful For
Diagnostic workup of hypoglycemia:
-Diagnosis of factitious hypoglycemia due to surreptitious administration of insulin
-Evaluation of possible insulinoma
-Surrogate measure for the absence or presence of physiological suppressibility of endogenous insulin secretion during diagnostic insulin-induced hypoglycemia (C-peptide suppression test)
Assessing insulin secretory reserve in selected diabetic patients (as listed below) who either have insulin autoantibodies or who are receiving insulin therapy:
-Assessing residual endogenous insulin secretory reserve
-Monitoring pancreatic and islet cell transplant function
-Monitoring immunomodulatory therapy aimed at slowing progression of preclinical, or very early stage type 1 diabetes mellitus
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumSpecimen Required
Patient Preparation:
1. Patient should fast for 8 hours.
2. For 12 hours before specimen collection do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.
Supplies: Aliquot Tube, 5 mL (T465)
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions: Centrifuge and aliquot serum into plastic vial within 2 hours of collection
Specimen Minimum Volume
0.75 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Frozen (preferred) | 30 days | |
| Refrigerated | 7 days |
Reference Values
1.1-4.4 ng/mL
Reference intervals have not been formally verified in-house for pediatric patients. The published literature indicates that reference intervals for adult and pediatric patients are comparable.
Day(s) and Time(s) Performed
Monday through Friday; 5 a.m.-12 a.m.
Saturday; 6 a.m.-6 p.m.
Test Classification
This test has been cleared, approved or is exempt by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
84681
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CPR | C-Peptide, S | 13037-7 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| CRPN | C-Peptide, S | 1986-9 |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Autopsy specimen | Reject |
Method Name
Electrochemiluminescence Immunoassay (ECLIA)
Forms
If not ordering electronically, complete, print, and send a General Request (T239) with the specimen.