Fasting Glucose (Serum) with 24-Hour Urine Collection for Glucose Excretion

Why This Test Is Done

Your doctor may order this test to evaluate blood sugar management, especially if you have diabetes or are at risk for it. It helps determine whether your kidneys are properly filtering glucose into urine, which can indicate kidney function or diabetes-related complications.

What to Expect Before the Test

You’ll need to fast (not eat or drink except water) for 8–12 hours before your blood draw. A 24-hour urine collection will also be required, starting after your fasting period. Follow your healthcare provider’s instructions precisely for accurate results.

What Happens During the Test

A blood sample is taken from a vein in your arm to measure fasting glucose levels. Separately, you’ll collect all urine over 24 hours in a container, discarding the first morning urine and saving the rest until the next day.

What the Results Mean

High fasting glucose or glucose in urine may signal diabetes, kidney issues, or poor blood sugar control. Low results may raise questions about metabolic health, but interpretation depends on clinical context and other test results.