In this article, an interference caused by hemoglobin H (Hb H), during the measurement of hemoglobin A1c (HbA1c) with ion exchange high pressure liquid chromatography (HPLC) method, was presented in blood sample of a 20-year-old male patient. HbA1c measurement was performed with Agilent 1200 HPLC system using a commercial Recipe HbA1c ion-exchange column. Hemoglobin electrophoresis was performe...