C-Peptide, Four Specimens

Casandra

Casandra Test Code LC68433Version 1 (DRAFT)

Performing Lab

Lab LabcorpLab Test ID 143324CPT Code 84681

C-Peptide, Four Specimens

Clinical Use

Use

The C-Peptide test is used to measure the level of insulin production by the pancreas. C-Peptide is a byproduct of insulin production and provides indirect insight into pancreatic function. This test is commonly performed to evaluate patients with suspected insulinoma, to distinguish between type 1 or type 2 diabetes, and to assess endogenous insulin production in patients taking exogenous insulin. The 'Four Specimens' panel allows for detailed temporal assessment by collecting multiple samples over time, typically in response to treatment or glucose challenge. This dynamic assessment aids clinicians in tailoring diabetes management and monitoring treatment efficacy.

Special Instructions

This panel is a series panel requiring multiple tubes to be drawn at different time points. Patients need to be treated with a drug or glucose before drawing subsequent samples following the initial collection. Do not collect this series until confirming with a clinician about the order's purpose. Patients on high-dose biotin supplements should discontinue their use at least 72 hours prior to sample collection to avoid interference in test results.

Limitations

This test may exhibit interference when the sample is collected from individuals taking high doses of biotin (vitamin B7, B8, or coenzyme R). It is crucial to ask patients about biotin supplementation to avoid compromised results. Additionally, the test may have limitations in settings where insulin antibodies are present or in post-prandial (after eating) states due to variations in C-Peptide levels. Interpretation should consider timing, clinical context, and other testing such as fasting status.

Test Details