Proceeds from website advertising help sustain Lab Tests Online. AACC is a not-for-profit organization and does not endorse non-AACC products and services.

Glucose Tests

Print this article
Share this page:
Also known as: Blood Sugar; Fasting Blood Sugar; FBS; Fasting Blood Glucose; FBG; Fasting Plasma Glucose; FPG; Blood Glucose; Oral Glucose Tolerance Test; OGTT; GTT; Urine Glucose
Formal name: Blood Glucose; Urine Glucose

Board approvedAll content on Lab Tests Online has been reviewed and approved by our Editorial Review Board.

At a Glance

Why Get Tested?

To determine if your blood glucose level is within a healthy range; to screen for and diagnose diabetes and prediabetes and to monitor for high blood glucose (hyperglycemia) or low blood glucose (hypoglycemia); to check for glucose in your urine

When to Get Tested?

Blood glucose: when you are older than 45 years or have risk factors for diabetes; when you have symptoms suggesting high or low blood glucose; during pregnancy; when you are diabetic, self-checks up to several times a day to monitor blood glucose levels

Urine glucose: usually as part of a urinalysis

Sample Required?

A blood sample drawn from a vein in your arm or a drop of blood from a skin prick; sometimes a random urine sample is used. Some diabetics may use a continuous glucose monitor, which uses a small sensor wire inserted beneath the skin of the abdomen to measure blood glucose at frequent intervals and provides a result.

Test Preparation Needed?

In general, it is recommended that you fast (nothing to eat or drink except water) for at least 8 hours before having a blood glucose test. For people with diabetes, glucose levels are often checked both while fasting and after meals to provide the best control of diabetes. For random, timed, and post-meal glucose tests, follow your health practitioner's instructions.