Hemoglobin A1c (HbA1c) is an important indicator of mean glycemia in patients with diabetes that has been shown to be strongly predictive of diabetes complications. More recently, it has been recommended for use in diagnosing diabetes.

Common hemoglobin variants have been shown to interfere with HbA1c results from some assay methods Clinically significant interferences may result in either over-treatment leading to hypoglycemia or under-treatment leading to hyperglycemia and heightened risk of diabetes complications. Interferences can also impact the diagnosis of diabetes.

In the U.S. and worldwide hemoglobin S is the most common hemoglobin variant; the prevalence is estimated to be 6-8% in African Americans and as high as 40% in parts of central Africa. Hemoglobin C is second most common in the U.S. followed by E and D Punjab; worldwide hemoglobin E is second most common, followed by C and D Punjab.

It is therefore important to identify which methods show interference from one or more of these variants by evaluating new methods, and periodically re-evaluating existing methods where the effects of potential interferences may have changed due to reagent lot changes and/or software revisions.