About This Test

The hemoglobin A1C (HbA1c) test measures your average blood sugar levels over the past 2-3 months. It is the primary test for diabetes management and diagnosis.

What is A1C?

Hemoglobin is a protein in red blood cells that carries oxygen. When glucose enters your bloodstream, it attaches to hemoglobin. The A1C test measures what percentage of your hemoglobin is coated with sugar.

A1C Results Interpretation

  • Normal: Below 5.7%
  • Prediabetes: 5.7% to 6.4%
  • Diabetes: 6.5% or above
  • Diabetes management goal: Usually below 7% (individualized by doctor)

Why Get Tested?

  • Diagnose prediabetes and diabetes
  • Monitor diabetes treatment effectiveness
  • Reduce risk of diabetes complications
  • Track blood sugar control over time

Test Preparation

Test Preparation

Fasting: Not required - you can eat and drink normally before the test.

What to Expect

  • Simple blood draw from a vein in your arm
  • Results typically available within 1-3 days
  • Test takes only a few minutes

Frequency of Testing

  • Diabetes diagnosis: At least twice a year if stable
  • Prediabetes: Annually
  • Diabetes management: Every 3-6 months depending on treatment
  • Pregnancy with diabetes: Monthly or more frequently

Understanding Your Results

Understanding Your Results

Below 5.7% - Normal

Your average blood sugar is in the normal range. Continue healthy habits.

5.7% - 6.4% - Prediabetes

Your blood sugar is higher than normal. Without intervention, many people develop type 2 diabetes within 10 years. Lifestyle changes can prevent or delay diabetes.

6.5% or Above - Diabetes

Indicates diabetes. Your doctor will confirm with additional testing and discuss treatment options.

For Those Managing Diabetes:

  • Below 7%: Good control (for most adults)
  • 7% - 8%: May be acceptable for some individuals
  • Above 8%: Blood sugar control needs improvement

Factors That Can Affect A1C

  • Anemia: May falsely lower A1C
  • Kidney disease: May affect accuracy
  • Recent blood transfusion: Can skew results
  • Pregnancy: A1C may be less reliable
  • Certain medications: HIV medications, some antibiotics

Related Tests

  • Fasting plasma glucose
  • Oral glucose tolerance test
  • Continuous glucose monitoring
  • Fructosamine test (alternative when A1C is unreliable)

Sources

Last Reviewed: April 2026