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Test ID CPR C-Peptide, Serum

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

Reporting Name

C-Peptide, S

Specimen Type

Serum


Specimen Required


Patient Preparation:

1. Patient should fast for 8 hours.

2. For 12 hours before this test do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions:

1. Serum gel tubes should be centrifuged within 2 hours of collection.

2. Red-top tubes should be centrifuged and aliquoted within 2 hours of collection.


Specimen Minimum Volume

0.4 mL

Specimen Stability Information

Specimen Type Temperature Time
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.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

84681

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CPR C-Peptide, S 1986-9

 

Result ID Test Result Name Result LOINC Value
CRPN C-Peptide, S 1986-9

Test Classification

This test has been cleared or approved 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.

Forms

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