Overview
Glucose is the body’s main source of energy. A fasting glucose test shows how effectively the body regulates blood sugar.
Why it's done
It is used to screen for diabetes, in at-risk groups (overweight, family history) and when symptoms such as thirst, frequent urination or fatigue are present.
How to prepare
Fasting for 8–12 hours is required. Water is allowed. The test is usually done in the morning.
What to expect
Blood is drawn from a vein. The procedure is quick and nearly painless.
Understanding the results
A fasting value of 3.9–5.5 mmol/L is considered normal. 5.6–6.9 indicates prediabetes; 7.0 or above suggests possible diabetes and needs confirmation. Interpretation should be done by an endocrinologist.