A new approach to photometry of glycated hemoglobin in human blood.

This new approach to measurement of glycated hemoglobin (Hb A1) is a three-step procedure involving (a) conversion of oxyhemoglobin into NO-hemoglobin by sodium dithionite and sodium nitrite in the presence of inositol hexaphosphate; (b) incubation with haptoglobin, which preferentially binds glycated hemoglobin; and (c) determination of the hemoglobin/haptoglobin complex by its peroxidase activity in acid buffer. The procedure is suitable for automated analysis with instruments that are capable of adding a starting reagent. We describe preliminary adaptations for the Abbott VP and Hitachi 705 analyzers and demonstrate the correlation of results with Hb A1 concentrations determined by ion-exchange chromatography.