Glucose in Serum (24-Hour Profile)

This test is done to measure the amount of glucose, or sugar, in your blood. It helps your doctor check how well your body manages blood sugar and screen for conditions such as diabetes or prediabetes.

Your healthcare provider may order this test if you have diabetes, prediabetes, or if you’re experiencing symptoms like frequent urination, excessive thirst, or unexplained weight changes. It may also be used to evaluate how well your current glucose management plan is working or to check for conditions like hypoglycemia or hyperglycemia.

The test works by measuring the concentration of glucose in a small sample of your blood. Glucose is your body's main source of energy, and hormones like insulin help keep its levels within a healthy range.

Blood samples are collected from a vein in your arm at regular intervals (typically every 2–4 hours) over 24 hours. The glucose levels in each serum sample are measured using an enzymatic method to determine your blood sugar concentration at different times of the day.

A small blood sample is usually collected from a vein in your arm or from a fingertip. Depending on the type of test, your doctor may ask you to fast for 8 to 12 hours beforehand, so follow all instructions you receive before your appointment.

No special preparation is needed for this test. You may continue your normal activities, but avoid taking any glucose-containing medications or supplements immediately before testing. If you’re on insulin or other diabetes medications, your provider will guide you on timing.

During the test, a healthcare professional will clean the collection site, draw your blood, and place a small bandage over the area. The procedure usually takes only a few minutes, and most people feel just a quick, mild pinch.

You’ll have multiple blood draws over 24 hours, usually at home or in a clinic. Each draw is quick and may cause a slight pinch. Your provider will explain the process and ensure you’re comfortable throughout.