C-Peptide, Serum, C Peptide, Serum
Antrim #18205, EPIC: LAB5802, CPEP
The patient should be fasting prior to specimen collection.
Specimen Collection Criteria
Collect: One Gold-top SST tube. (Minimum Whole Blood: 2.0 mL)
Send specimen to the Laboratory immediately after collection for processing.
Physician Office/Draw Specimen Preparation
Let specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Transfer serum to a plastic transport tube and freeze (-20°C/-4°F or below) immediately. (Minimum Serum: 0.5 mL)
Preparation for Courier Transport
Transport: Serum aliquot, frozen (-20°C/-4°F or below). (Minimum Serum: 0.5 mL)
- Samples that have not been collected and processed as indicated.
- Plasma specimens.
- Severely lipemic, icteric, or hemolyzed specimens.
Tubes are placed on the Abbott input / output module for centrifugation and testing by the automated line instruments.
Specimen Stability for Testing:
Room Temperature (20-26°C or 68-78.8°F): Unacceptable
Refrigerated (2-8°C or 36-46°F): 48 hours for inpatients only.
Frozen (-20°C/-4°F or below): 7 days
Specimen Storage in Department Prior to Disposal:
Refrigerated (2-8°C or 36-46°F): 7 days
Royal Oak Automated Chemistry Laboratory
Monday – Friday.
Results available within 2 business days.
Fasting: 0.8-5.2 ng/mL.
Insulin and C-Peptide are released in equimolar amounts from the beta cells of the pancreas. The half-life of insulin and C-Peptide is 5-10 minutes and 30-35 minutes, respectively. Because of this longer half-life, C-Peptide levels are often used as an indicator of beta-cell function. It has been demonstrated that individuals with type 1 diabetes who maintain higher C-Peptide levels have fewer complications.
C-Peptide levels may aid in distinguishing type 1 and type 2 diabetes. C-Peptide is also useful in the determination of endogenous insulin secretion and the diagnosis of insulinoma.
In insulinoma, C-Peptide levels should parallel those of insulin. Factitious hyperinsulinism (i.e., exogenous insulin administration) will have high insulin but low C-Peptide levels.
Automated Chemistry Laboratory – RO
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