Hemoglobin A1c
Also known as:
HbA1c, glycated hemoglobin
Your average blood sugar over about three months, and the main test for diagnosing and tracking diabetes.
Written and reviewed by Farhan Tahir, MD · Last reviewed
VIDEO LESSON
What it measures
Glucose sticks to hemoglobin in red blood cells. Because red cells live about three months, A1c reflects average glucose over that time.
Reading the results
• Below 5.7%: normal
• 5.7% to 6.4%: prediabetes
• 6.5% or higher: diabetes, confirmed with repeat testing
• Many adults with diabetes aim for below 7%, individualized
When it misleads
• Anemia, recent blood loss or transfusion
• Kidney failure and pregnancy
• Some hemoglobin variants
• In these cases, fasting glucose, an OGTT or CGM are better guides
Key studies and references
Educational content only, written and reviewed by Farhan Tahir, MD. It does not replace individual medical advice. For sudden chest pain, trouble breathing or stroke symptoms, call 911.
AT A GLANCE
Test type
Blood sugar
Also known as
HbA1c, glycated hemoglobin
Reviewed by
Farhan Tahir, MD
Questions about your own care?
Dr. Tahir’s team offers consults through Youthful Medicine.
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