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Test Code CPTDE C-Peptide, Serum

Specimen Type

Preferred: Serum

Acceptable: Plasma


Preferred: Serum Red Top tube or Gold SST

Acceptable: Lithium Heparin (Mint Green or Dark Green)

Preferred Volume

5 mL

Offsite Collection Instructions

1. Serum or plasma should be centrifuged and aliquoted within 2 hours of collection.

2. Aliquoted samples should be refrigerated at 2-8°C prior and during transportation.

3. If above criteria are not met, specimen will be rejected.

UCMC Collection Instructions

1. Samples need to be received in the lab within 2 hours of collection at room temperature.

2. Greater than 2 hours must be refrigerated at 2-8°C.

3. If the specimen cannot be sent to the lab within 4 hours of collection, it must be spun, aliquoted and refrigerated at 2-8°C.

4. All unspun specimens greater than 4 hours will be rejected.  

5. If above criteria are not met, specimen will be rejected.



Turnaround Time

4 hours

STAT Availability

Not Available

Test Usage

Aid in the diagnosis and treatment of patients with abnormal insulin secretion.

Test Methodology

Chemiluminescent enzyme immunoassay

CPT Code


Test Includes

Quantitative analysis of c-peptide in serum 

Reference Range

0.3 – 2.35 pmol/mL

Critical Results


Minimum Volume

2 mL

Fee Code