Blood haemoglobin determination as haemiglobin isothiocyanate

A method for the determination of blood haemoglobin, as haemiglobin isothiocyanate was developed and evaluated. Appropriate concentrations of the reagents were chosen to minimize the risk of turbidity from plasma proteins. The stability constant of the isothiocyanate derivative was measured, then used to select a KSCN concentration high enough to bring about complete transformation. The method compared fairly well with the standard HiCN method, and with automatic haemoglobin measurements. The proposed procedure has no particular analytical advantages over the standard HiCN method, the haemiglobin azide method, or the alkaline haematin method; but it uses low-toxicity, non-hazardous chemicals.