What is the reference interval for hemoglobin A1c?

Updated: Dec 26, 2018
  • Author: Gary L Horowitz, MD; Chief Editor: Thomas M Wheeler, MD  more...
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The reference range for hemoglobin A1c levels in healthy adults is 4.8-5.7%.

The decision limits for nonpregnant adults, according to the American Diabetes Association, are as follows [1] :

  • The diagnostic criterion for diabetes is a hemoglobin A1c level greater than or equal to 6.5% NGSP units
  • For patients with diabetes mellitus, the goal of therapy is a level below 7.0%, in general
  • A goal of less than 6.5% may be appropriate for some patients who can achieve this without significant episodes of hypoglycemia (eg, persons newly diagnosed with diabetes, individuals with diabetes who are managed with diet and exercise alone)
  • For elderly patients, patients with a short life expectancy, and patients with frequent/severe episodes of hypoglycemia, a less strict goal of below 8% may be more appropriate and must be determined on an individualized basis

Note: Different associations have different hemoglobin A1c treatment goals; eg, the American Association of Clinical Endocrinologists recommends a treatment goal of less than 6.5% for most patients.

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