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Also known as: Insulin C-peptide; Connecting Peptide Insulin; Proinsulin C-peptide
Formal name: C-peptide
Related tests: Insulin; Glucose

At a Glance

Why Get Tested?

To help evaluate insulin production by the beta cells in the pancreas or to help determine the cause of low blood glucose (hypoglycemia)

When to Get Tested?

When you have diabetes and your health practitioner wants to determine if you are producing enough of your own insulin or if it is time to supplement oral medication with insulin injections or an insulin pump; when your health practitioner suspects that you have insulin resistance; when you have documented hypoglycemia

Sample Required?

A blood sample drawn from a vein in your arm and sometimes a 24-hour urine sample

Test Preparation Needed?

Fasting for 8 to 10 hours before blood testing is usually required.