A new reagent for the rapid determination of total hemoglobin as hemiglobincyanide in blood containing carboxyhemoglobin

Abstract

Kinetics of conversion of HbCO to HiCN with various K 3Fe(CN) 6—KCN reagents was examined photometrically. Complete conversion of HbCO to HiCN required about 8 hr, 150 min, and 50 min with Drabkin's reagent, that of van Kampen and Zijlstra, and that of Taylor and Miller, respectively. The absorbance at 540 nm was stabilized practically in 5 min even in CO-saturated blood when a reagent containing a 1600-fold excess of K 3Fe(CN) 6 to Hb iron was used. A slight increase in the absorbance was observed around 504 nm in the HiCN solution produced with the reagent. The absorbance at 540 nm in the solution, however, was stable until at least 120 min after mixing. From these findings, a reagent containing a 1600-fold excess of K 3Fe(CN) 6 to Hb iron and an incubation time of 5 min were used for the complete conversion of HbCO to HiCN. The stabilization of the absorbance at 540 nm was often prolonged to 10 min when the reagent was stored over 2 weeks. The reagent was compared with two other reagents, using 20 blood samples containing various amounts of HbCO, and proved to be suitable for the determination of total Hb in blood containing elevated HbCO as well as in ordinary blood.