C-peptide (Serum/Plasma) with 1-Hour Postprandial Measurement

Why This Test Is Done

Your doctor may order this test if you have diabetes or are suspected of having insulin resistance, or if you need to monitor how your body processes food and blood sugar after meals. It can also help diagnose conditions like type 1 or type 2 diabetes or rule out other causes of high blood sugar.

What to Expect Before the Test

You’ll typically fast for a few hours before the test, but the 1-hour postprandial (after-eating) sample is collected shortly after you’ve eaten a meal. Bring any medications you’re taking and let your healthcare provider know about allergies or conditions that might affect results.

How the Test Works

A small blood sample is taken from a vein, usually in your arm. The sample is analyzed to measure C-peptide levels, which reflect insulin production. This test helps distinguish between insulin-dependent and insulin-independent glucose regulation.

What the Results Mean

Results help determine if your pancreas is producing insulin normally after meals. Abnormal levels may indicate issues like diabetes, pancreatic disease, or other metabolic disorders. Your doctor will interpret results in the context of your symptoms and medical history.