Fasting Glucose

What is Fasting Glucose?

Fasting glucose measures the amount of sugar (glucose) in your blood after you haven't eaten for at least 8 hours. This "baseline" reading shows how well your body manages blood sugar without the influence of recent meals.

It's the most common test for screening and diagnosing diabetes and prediabetes.

Normal Ranges

Fasting Glucose	Classification
Below 100 mg/dL	Normal
100–125 mg/dL	Prediabetes
126+ mg/dL	Diabetes (requires confirmation)

Why It Matters

Diabetes Diagnosis

Two fasting glucose readings of 126 mg/dL or higher confirms diabetes. Early detection allows treatment before complications develop.

Prediabetes Detection

The 100–125 mg/dL range identifies prediabetes — a critical window for lifestyle intervention. Many people can prevent progression to diabetes at this stage.

Daily Regulation

Even within "normal" ranges, higher fasting glucose is associated with increased health risks. Optimal is generally below 90 mg/dL.

Fasting Glucose vs. HbA1c

Test	What It Shows
Fasting Glucose	Blood sugar at one moment
HbA1c	Average over 2–3 months

Both are useful — glucose for acute changes, HbA1c for long-term patterns.

What Affects Fasting Glucose

Sleep quality (poor sleep raises glucose)
Stress (cortisol raises glucose)
Dawn phenomenon (natural morning rise)
Medications
Recent illness