What's the difference between HbA1c and fasting glucose?

Fasting glucose shows your blood sugar at one moment in time. HbA1c shows your average blood sugar over 2-3 months, giving a much better picture of overall blood sugar control and diabetes risk.

Do I need to fast for this test?

No! Unlike fasting glucose, HbA1c can be done at any time of day without fasting. Eating before the test won't affect your results.

Can HbA1c diagnose diabetes?

Yes. An HbA1c of 6.5% or higher on two separate tests is used to diagnose diabetes. Levels of 5.7-6.4% indicate prediabetes.

How often should I test HbA1c?

For screening: annually if you have risk factors. For prediabetes: every 6-12 months to monitor progress. For diabetes: every 3-6 months depending on how well controlled your blood sugar is.

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Hemoglobin A1c (HbA1c) Blood Test

Name: Hemoglobin A1c (HbA1c) Blood Test
Brand: Justlabs
SKU: 0000496
Price: 7 USD
Availability: InStock

HbA1c

The HbA1c test shows your average blood sugar over the past 2-3 months - like a "blood sugar GPA" that reveals your overall glucose control.

The Hemoglobin A1c (HbA1c) test measures your average blood sugar levels over the past 2-3 months. Unlike a fasting glucose test that shows a single point in time, A1c reflects your overall glucose control.

This test is the gold standard for diagnosing and monitoring diabetes. It measures the percentage of hemoglobin (the oxygen-carrying protein in red blood cells) that has glucose attached to it. The higher your blood sugar, the more glucose attaches to hemoglobin.

A1c is particularly valuable because it is not affected by recent meals, stress, or illness - giving you a true picture of your metabolic health over time.

Price

Results

1-2 days

Lab Network

Quest

Fasting

Not Required

What's Measured

HbA1c

Estimated Average Glucose

What This Test Measures

This test measures the percentage of hemoglobin proteins in your blood that have glucose attached (glycated hemoglobin). Results are given as a percentage. Normal is below 5.7%, prediabetes is 5.7-6.4%, and diabetes is 6.5% or higher. The test also provides an Estimated Average Glucose (eAG) in mg/dL.

Who Should Consider This Test

Adults over 45 (or younger if overweight), anyone with risk factors for diabetes (family history, high blood pressure, PCOS, sedentary lifestyle), people with prediabetes monitoring their progress, and diabetics tracking long-term blood sugar control.

Health Insights

Conditions Screened

Type 2 diabetesPrediabetesType 1 diabetesGestational diabetes historyMetabolic syndrome

Related Symptoms

Increased thirstFrequent urinationUnexplained weight lossFatigueBlurred visionSlow-healing woundsTingling in hands/feetFrequent infections

When to Get Tested

No fasting required - test anytime! For screening, test annually if you have risk factors. If monitoring diabetes, test every 3-6 months. Some prefer morning testing, but timing doesn't affect results.

Understanding Your Results

Normal: Below 5.7% | Prediabetes: 5.7% - 6.4% | Diabetes: 6.5% or higher. Each 1% change in HbA1c corresponds to roughly 30 mg/dL change in average blood sugar. For diabetics, keeping HbA1c below 7% significantly reduces risk of complications.

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What to Expect

After placing your order, you'll receive an email from Rupa Health (our lab order partner) within 24 business hours to sign a consent form and schedule your blood draw at a Quest Diagnostics location.

The blood draw typically takes just a few minutes. Results are usually available within 1-2 business days and will appear in your secure Justlabs dashboard.

Our results include reference ranges and easy-to-understand indicators showing whether your values are within normal limits.