Evaluation of a new commercial assay kit for quantification of lactate dehydrogenase isoenzyme 1 in serum.

A new method for measuring lactate dehydrogenase (EC 1.1.1.27) isoenzyme 1 using sodium perchlorate as a chaotropic chemical selective inhibitor of all lactate dehydrogenase isoenzymes containing M-subunit was evaluated. Results with this method were precise (between-day coefficient of variation less than 9%), highly linear (coefficient of correlation = 0.9998) and correlated well with lactate dehydrogenase isoenzyme 1 as determined by the conventional immunological method (coefficient of correlation = 0.976). The reference interval for 307 healthy subjects was estimated to be 23-46 U/l (95% central range, determined non-parametrically). Being simple, convenient and amenable to automation, the method provides a substantial saving in labour and reagent costs when compared with alternative analytical approaches.