Glucose measured in plasma (3 AM)

Why This Test Is Done

Doctors may order this test to evaluate how your body handles glucose during sleep, especially in people with suspected or known diabetes, metabolic disorders, or those undergoing certain medical evaluations. It helps assess overnight glucose fluctuations that standard fasting tests may miss.

What to Expect Before the Test

You’ll typically fast for 8–12 hours before the test. Avoid eating, drinking (except water), smoking, or taking medications unless instructed otherwise. Your blood will be drawn from a vein in your arm by a healthcare professional.

What the Test Results Mean

This test measures the concentration of glucose (sugar) in your plasma at a specific time of night. Results help identify patterns in your blood sugar, such as whether your body produces enough insulin or if there’s an issue with how your body uses glucose.

Common Causes for Testing

This test may be recommended if you have symptoms like frequent urination, excessive thirst, unexplained weight changes, fatigue, or if you’re at risk for diabetes. It’s also used in research or clinical studies to monitor overnight glucose trends.