[Turning point in quality control: problems at present and themes in future].

Quality control in clinical laboratory has a longer than forty-year history after its introduction. At present, quality control has been considered as one of essential tools to evaluate the quality of clinical laboratory data. However, several problems to be solved have still remained. I clarify the problems at present and declare the themes in future. Problems of internal quality control (IQC): Analytical precision of clinical laboratory test has remarkably improved recent years because of the advancement of technologies including analytical procedures and instruments. However, analytical accuracy has not attained the subjects. Furthermore, QC procedures have been converting into subjects and it has been generally considered that using a lot of QC material and QC method is a good manner. As a result, fundamental control procedures such as material control, reagent control and instrument maintenance have been ignored. Problems of external quality control (EQC): It has been considered that EQC serves as an indicator of analytical accuracy and shows the average analytical performance of all participants. However, some problems have remained as follows: (1) Problem of samples for proficiency testing. (2) Problem of classification of peer group. (3) Problem of target value. (4) Problem of evaluation criteria. In general, various IQC methods have been used without careful consideration. However, I would like to emphasize that we have to select the best QC method which can detect the error to be checked according to the method performance. For this reason, we have to grasp the purpose of QC and be careful to not change the subjects into the QC procedure.(ABSTRACT TRUNCATED AT 250 WORDS)