Sign in →

Test Code C Pep C-Peptide

Aliases

C-Peptide, Serum

Useful For

IVD test use for the quantitative measurement of C-peptide in human serum. C-peptide concentration provides an accurate assessment of β-cell function and has become an important marker of insulin secretion in patients with diabetes. C-peptide assessment is also useful in the diagnosis of insulinoma/endogenous hyperinsulinemia.

Patient Preparation

Fasting at the request of physician

Special Collection Instructions

Allow specimen to clot completely at room temperature for 45 min, then centrifuge. Separate serum from cells ASAP then freeze serum.

Collection Method

Venous collection

Minimum Volume

0.5 mL serum

Container

Red / Additive Free

Preferred Specimen

Frozen Serum

Acceptable Specimens

Frozen Serum

Reference or Target Ranges

Fasting 0.23 – 0.86 nmol/L
120 min 0.34 – 2.33 nmol/L

Reportable Units

nmol/L

Critical Value

Not defined for this assay

Reasons for Rejection

Hemolysis Threshold No Interference up to 440 mg/dL (See Additional Information/Important Notes section)
Icterus Threshold N/A
Lipemia Threshold No Interference up 1,600 mg/dL
Interfering Subtances/Other Wrong container, labeled improperly, serum not frozen

Specimen Stability

Ambient N/A
Refrigerated (2°C to 8°C) 1 day
Frozen(-70°C to 0°C) 60 days

Performance Information

Days and Time Performed Monday – Friday 8 AM – 5 PM
Expected Turn Around Time 5 days excluding weekends and holidays
Stat Availabilty Per request of clinician
Performing Bench Diagnostic Diabetes Lab
Methodology/Method Description Tosoh AIA-900 – Two-site immunoenzymometric assay

Special Handling

Allow specimen to clot completely at room temperature for 45 min, then centrifuge. Separate serum from cells ASAP and freeze serum. Avoid repeated freeze/thaw cycles.

Additional Information/Important Notes

For patients that are being treated with Asfotase Alfa (Strensiq®) elevated test results are likely to occur using this method. Results should not be used for patients receiving Asfotase Alfa treatment. An alternative test method should be used that does not utilize alkaline phosphatase technology. All results should be interpreted with respect to the clinical picture of the patient

Hemolysis Note: if a specimen is observed to be grossly hemolyzed, the laboratory will contact the ordering physician to advise them that the test can be canceled or performed with a note advising clinicians to interpret the results with caution.

CPT Codes

84681