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C-Peptide, Serum

Additional Codes

Primary ID

Epic Code

Mayo Test ID

CPEPN

 LAB2478

CPR

 

Reporting Name

C-Peptide, S

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

Method Name

Electrochemiluminescence Immunoassay (ECLIA)

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Specimen 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

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

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 13037-7

Test Classification

This test has been cleared, approved, or is exempt by the US 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.

Report Available

1 to 3 days

Specimen Retention Time

2 weeks

NY State Approved

Yes

Forms

If not ordering electronically, complete, print, and send a General Request (T239) with the specimen.