Standardisation of haemoglobinometry: History and new challenges

Abstract

During the 1950s several attempts were made to standardise the measurement of the haemoglobin concentration in human blood, for which numerous different methods were in use giving widely different results. In 1966, a consensus was reached on the general use of a photometric determination after conversion of all haemoglobin present in the sample into cyanmethaemoglobin (haemiglobincyanide; HiCN). Standardisation of the method was attained on the basis of the absorptivity (extinction coefficient) of HiCN at 540 nm, which had been exactly determined by means of various methods, and was established to be 11.0 1/mmol/ cm by the International Committee for Standardization in Haematology, which had just been founded, and which actually started its activities by setting up an Expert Panel on Haemoglobinometry. This panel has been active ever since, establishing and revising recommendations for the standardised HiCN method and organising and supervising production and distribution of an international reference preparation, a sterile ampouled HiCN solution of exactly known concentration. The HiCN method was well-accepted, soon came into general use, and performed satisfactorily for many years. With the advent of laboratory automation a new diversity of methods arose. The manual HiCN method was phased out as a routine method and gradually became the reference method with which the current methods should agree. The main challenge now is to maintain a worldwide comparability of results in the face of a continual change in methodology.