Glucose in Serum (24-hour profile)

Why This Test Is Done

Your doctor may order this test if they suspect you have diabetes, prediabetes, or another condition that affects how your body processes glucose. It can also help monitor how well treatments like medication or insulin are working. Unlike single-point glucose checks, this profile gives a full picture of your glucose fluctuations.

What to Expect Before the Test

You’ll typically fast (not eat or drink except water) for 8 to 12 hours before your first blood draw. Follow your doctor’s instructions carefully. Blood samples will be taken at regular intervals over 24 hours, often at home or in a clinic, to capture glucose levels during eating, sleeping, and activity.

How the Test Works

Blood is drawn from a vein (usually in your arm) at set times—often including before meals, during meals, and after meals. The glucose levels in your serum (liquid part of blood) are measured using a sensitive laboratory method to detect small changes throughout the day.

What the Results Mean

Results show your glucose levels at different times. High or low readings at certain times may indicate how well your body regulates blood sugar. Your doctor will compare these results with your symptoms and other health information to diagnose or guide treatment.