C-peptide

Understanding the marker

C-peptide is released when the pancreas makes insulin. Measuring it helps assess the body's own insulin production.

C-peptide is assessed with glucose measured at the same time, kidney function and any treatment. These show whether insulin production is appropriate for the blood sugar level. Preparation depends on the ordered test; follow its specific instructions.

What does high C-peptide mean?

A high result may reflect more insulin production or slower removal of C-peptide by the kidneys. It is assessed with the glucose level, kidney function and any treatment, rather than used alone to identify a cause.

What does low C-peptide mean?

A low C-peptide result may reflect less insulin production, but insulin needs also fall when blood sugar is low. The glucose result taken at the same time and any treatment are essential to interpretation.