Insulin and C-Peptide

CPT: 83525; 84681
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Test Details


  • C-Peptide and Insulin


Reflects the patient's beta cell function. It, therefore, is a marker for endogenous insulin production with or without exogenous insulin injection. C-peptide is not affected by the presence or absence of insulin antibodies.


Electrochemiluminescence immunoassay (ECLIA)

Specimen Requirements




1 mL

Minimum Volume

0.5 mL (Note: This volume does not allow for repeat testing.)


Red-top tube or gel-barrier tube


If a red-top tube is used, transfer separated serum to a plastic transport tube. Avoid hemolysis.

Storage Instructions


Stability Requirements



Room temperature

1 day


14 days


14 days

Freeze/thaw cycles

Stable x3

Causes for Rejection

Citrate plasma specimen; hemolyzed specimen

Clinical Information

Special Instructions

This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample.


Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
213660 Insulin and C-Peptide, Serum 004333 Insulin uIU/mL 20448-7
213660 Insulin and C-Peptide, Serum 010109 C-Peptide, Serum ng/mL 1986-9

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