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HelpTEST ID CPR C-Peptide, Serum
Reporting Name
C-Peptide, SSpecimen Type
SerumSpecimen Required
Patient Preparation:
1. Patient should fast for 8 hours.
2. For 12 hours before specimen collection, patient should not take multivitamins or dietary supplements (eg, hair, skin, and nail supplements) containing biotin (vitamin B7).
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
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 a 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 |
Method Name
Electrochemiluminescence Immunoassay (ECLIA)
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | OK |
| Autopsy specimen | Reject |
Reference Values
1.1-4.4 ng/mL
Reference interval applies to fasting patients.
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) Performed
Monday through Saturday
Report Available
1 to 3 daysSpecimen Retention Time
2 weeksPerforming Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
84681
Forms
If not ordering electronically, complete, print, and send a General Request (T239) with the specimen.
Useful 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