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Test Mnemonic CPEP C-Peptide, Serum

Additional Codes

Mayo Test ID
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

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type

Serum


Specimen Required


Patient Preparation: 12 hours before this test do not take multivitamins or dietary supplements containing biotin or vitamin B7, which are 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. Fasting: 8 hours

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

3. 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.

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.

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

Method Name

Electrochemiluminescence Immunoassay

Forms

If not ordering electronically, complete, print, and send a General Request Form (T239) with the specimen (http://www.mayomedicallaboratories.com/it-mmfiles/general-request-form.pdf).