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HelpOrder Code LAB2522 C-Peptide, Serum
Additional Codes
Mayo Test Code: CPR
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, 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 |
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
CPT Code Information
84681
Method Description
The Roche Elecsys C-peptide assay is a 2-site immunometric (sandwich) assay using electrochemiluminescence detection. Patient specimen, biotinylated monoclonal C-peptide specific antibody, and monoclonal C-peptide-specific antibody labeled with a ruthenium react to form a complex. Streptavidin-coated microparticles act as the solid phase to which the complex becomes bound. Voltage is applied to the electrode inducing a chemiluminescent emission from the ruthenium, which is then measured against a calibration curve to determine the amount of C-peptide in the patient specimen.(Package insert: Elecsys C-peptide. Roche Diagnostics; V 2.0 English, 10/2022)
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | 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.