Artificially low hemoglobin A1c caused by use of dapsone.

OBJECTIVE: To describe a case of artifactually decreased hemoglobin Alc (HbAlc) attributable to use of dapsone. METHODS: We present a detailed case report and results of a related literature search. In addition, potential causes of artifactually lowered HbAlc values are discussed. RESULTS: A 35-year-old patient with type I diabetes had high home-monitored blood glucose values, high clinic plasma glucose determinations, increased fructosamine levels, and low HbAlc values. The lowering of the HbAlc level was associated with use of dapsone, and the decrease in HbAlc value was proportional to the dose of dapsone. A literature search revealed one previous report of artifactual lowering of the HbAlc value, in which high methemoglobin levels were found and thought to be the cause of the artifactually decreased HbA1c. CONCLUSION: By increasing methemoglobin levels and decreasing erythrocyte survival, dapsone can artifactually lower HbA1c. Clinicians should be aware of this potential side effect of dapsone.