Evaluation of two types of 'medically significant error limits' and two quality control procedures on a multichannel analyzer.

Analytical error limits based on two different concepts of "medical significance" are derived. The ability of the system to detect medically significant errors using standard (1(3s] and enhanced (mean and range) quality control procedures is investigated. Error detection is found to be adequate for most analytes when error limits are based on physicians' opinions and a mean and range quality control system is used. Error detection is unsatisfactory when error limits based on intraindividual biological variation are used and this cannot be improved by using better quality control systems. The limiting factor is analytical precision. The use of error limits based on biological variation as proposed by major clinical chemistry professional bodies cannot be achieved using most current types of analytical technology.