C-peptide Blood Test - More Information

The C-peptide test, sometimes known as a C-peptide blood test and C-peptide lab test, measures C-peptide blood level.

C-peptide is a peptide molecule that consists of amino acids and joins two parts of the proinsulin molecule together. The C-peptide test is often useful when measured in conjunction with the insulin test as C-peptide and insulin are bound together when made by the pancreas and are secreted in relatively equal amounts. As a result, C-peptide is useful as a blood marker to differentiate insulin produced naturally versus injected externally.

Although C-peptide levels are related to insulin levels, C-peptide typically does not affect the blood glucose levels as measured by the glucose test. However, C-peptide can be useful in determining if excessive medication use or tumors are causing low blood sugar levels. C-peptide levels are also useful in determining if someone has type I diabetes as the C-peptide levels are typically low in those instances.

To get a C-peptide test near you at a Quest Diagnostics lab, just order online and get your blood drawn at the selected lab. Once the C-peptide lab results are ready, they will be available for electronic download. As can be seen on the sample C-peptide lab report above, the C-peptide blood level is reported as a number and can be compared against the reference range provided by the lab.

Overall, along with diabetes markers measured in the diabetes management panel, C-peptide levels are being used more regularly in assessing overall diabetic control. When used in this way, C-peptide testing is often performed in conjunction with the hemoglobin A1c test.