Statistical Evaluation of the Determination of Red Cell Acetylcholinesterase Activity

Abstract

The dithiobisnitrobenzoic acid method for the determination of red cell acetylcholinesterase (AChE) activity, performed by means of a diagnostic ‘kit’, has been evaluated. The experimental design known as nested design has been used in order to determine the precision of the method and the influence that variability outside the laboratory (including the biological variability of each subject) has on the clinical significance of the results. It has been found that the most widely used procedure — i.e. one blood collection, one subsample, two replicates — can be considered satisfactory, since the AChE value obtained has a coefficient of variation of approximately nine.