The following are some uses of C-peptide testing:

Additionally, with the rising incidence of type 2 diabetes in younger patients and newer medications aimed at preserving insulin production, the test will likely become more important. While not a regularly ordered lab test, C-peptide testing can be very useful in certain medical situations.

This test may be done in conjunction with an insulin test or a glucose test. In particular, C-peptide testing can be used to help evaluate the production of insulin made by the body (endogenous) and to help differentiate it from insulin taken in as diabetic medication (exogenous) which not generate C-peptide. Since C-peptide is produced at the same rate as insulin, it is useful as a marker of insulin production. When insulin is released from the beta cells into the blood in response to increased levels of glucose, equal amounts of C-peptide are also released. Insulin is vital for the transport of glucose into the body’s cells and is required on a daily basis. In the pancreas, within specialized cells called beta cells, proinsulin, a biologically inactive molecule, is split apart to form one molecule of C-peptide and one molecule of insulin. This test measures the amount of C-peptide in a blood or sometimes a urine sample. It is important to know that you must use the range supplied by the laboratory that performed your test to evaluate whether your results are “within normal limits.”įor more information, please read the article Reference Ranges and What They Mean.Ĭ-peptide is a substance, a short chain of amino acids, that is released into the blood as a byproduct of the formation of insulin by the pancreas. This is a reason why so few reference ranges are provided on this site. While accuracy of laboratory testing has significantly evolved over the past few decades, some lab-to-lab variability can occur due to differences in testing equipment, chemical reagents, and techniques. Values that are outside expected ranges can provide clues to help identify possible conditions or diseases. By comparing your test results with reference values, you and your healthcare provider can see if any of your test results fall outside the range of expected values. They are sometimes called “normal” values. Reference ranges are the values expected for a healthy person. Their meaning comes from comparison to reference ranges. Laboratory test results are not meaningful by themselves. If you do not have your lab report, consult your healthcare provider or the laboratory that performed the test(s) to obtain the reference range. They are typically found to the right of your results. The reference ranges for your tests can be found on your laboratory report.

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