Hemoglobin A1c values of 5.7-6.4 percent indicate an increased risk for developing diabetes mellitus. Hemoglobin A1c values greater than or equal to 6.5 percent are diagnostic of diabetes mellitus. Diagnosis should be confirmed by repeating the Hb A1c test.
This boronate affinity Hb A1c method provides accurate analytical results in the presence of nearly all hemoglobin variants. Hb F higher than 10 percent of total Hb may yield falsely low results. Conditions that shorten red cell survival, such as the presence of unstable hemoglobins like Hb SS, Hb CC, and Hb SC, or other causes of hemolytic anemia may yield falsely low results. Iron deficiency anemia may yield falsely high results.