[Quality control of enzyme immunoassay--assurance and control of analytical sensitivity, accuracy and precision].

Although the basic concept for quality control of enzyme immunoassay (EIA) is the same as that of quality control of the usual chemical analysis, immunological analytic methods including enzyme immunoassay have some specific features depending on the method as compared with the chemical method. In addition to the usual QC method, therefore, it is necessary to add some QC techniques to control the variables derived from the method. In accuracy control of EIA, standard materials, reagents and analytical equipment will be the major sources of error. Points to be considered in accuracy control are described. In precision control of EIA, between-run precision is generally larger than within-run precision. In consideration of the characteristics, mean-Rs-R control chart method and Z-V control chart method appropriate for immunological method are described. Analytical sensitivity expressed as detectability and detection limits is very important in EIA. A procedure to determine the detection limits is described in detail. Between reagent lot difference in immunological reagent is considerably larger than that of chemistry reagent and a shift of the point on the control chart is not adequate to assess the reliability of the patient data. Therefore, an evaluation method of the between reagent lot difference is described. General procedures of precision control are not described here because the procedures are well known.