Carboxyhaemoglobin: a possible reference material for haemoglobin assay.

The inter- and intralaboratory quality control of haemoglobin estimation in remote laboratories requires a more rugged control haemolysate than is commercially available. The stabilities of oxyhaemoglobin and carboxyhaemoglobin forms of an ethanediol-containing haemolysate were studied over a three-year period. From the results obtained, carboxyhaemoglobin under nitrogen is proposed as a possible candidate reference material for haemoglobin assay.

The coefficient of analysis, a new figure of merit for laboratory performance.

A simple statistic has been developed to determine a figure of merit for overall laboratory performance. This simple statistic, the coefficient of analysis, relates for the first time both the imprecision and the inaccuracy of a laboratory analysis to a single value that clinical chemists will easily understand. In the derivation of the coefficient of analysis, we also define two secondary statistics: the coefficient of bias, which is mathematically similar to the CV and represents the inaccuracy of an analysis, and the coefficient of accuracy, which is mathematically represented as 100 minus the coefficient of bias and is a measure of the accuracy of the analysis.