HbA1c Below the Reportable Range

Abstract

This case report concerns a 71 year old female patient who had a very low glycosylated hemoglobin (HbA1c) despite having a high level of fasting blood glucose. The patient had a decreased erythrocyte count, elevated red blood cell indices, and a reticulocyte count with no evidence of hemoglobinopathy. She reported receiving hydroxychloroquine treatment for systemic lupus erythematosus. Subsequent laboratory investigations revealed hemolysis with formation of cold agglutinin. Because cold agglutinins can interfere with HbA1c assays, the specimens were reanalyzed after warming. The complete blood count results improved, but the HbA1c result did not change. In patients in whom medications and/or medical conditions may interfere with HbA1c levels, alternative measures of glycemic control, such as fructosamine, could be beneficial.

Keywords: cold agglutinin; complete blood count; false low HbA1c; fructosamine; high-performance liquid chromatography; systemic lupus erythematosus.