Evaluation of the causes of error in analysis of routine tests.

The retrospective study is one of the part of quality control circle which will be improve the reliability and efficiency of laboratory service. We evaluated the result from the Department of Clinical Chemistry, Faculty of Medical Technology, Mahidol University which served routine analysis for out-patients and in-patients from Siriraj Hospital. After careful screening the random and systematic error we followed the design in planning of laboratory management between June to December 1987, there are 72 cases which had a definitive problem and error which was clarified in three categories:- preanalytical process 15.3%, analytical process 65.3%, and post analytical process 19.5%.