[Antistreptolysin O].

Automated analyzers based on the quantitative immunochemical methods have been developed and can allow quantitative measurements of antistreptolysin O concentrations in the clinical laboratories. Automated ASO determinations improve in point of operation, time, effort, precision and accuracy, compared with the usual semiquantitative methods of tube dilution techniques based on the method of Rantz and Randall or some modification thereof, microtitration of the Edward method and agglutination test using latex or other particles. However, confusion and many kinds of problems have been brought about by the rapid development of automated ASO measurements in routine use. The principle quantitative immunochemical measurements of automated ASO determinations are immune agglutination assays, which are nephelometric immunoassay (NIA), latex agglutination photometric immunoassay (LAPIA) and turbidimetric immunoassay (TIA). Principles and methods of these automated immunoassay, reagents, ASO standard serum, automated analyzers, precision and accuracy, the present conditions and problems of automated analysis in the clinical laboratories were discussed in comparison with usual semiquantitative measurements. There was a good correlation between automated immune agglutination assay (NIA, LAPIA and TIA) and the usual semiquantitative assay. However, the quantitative accuracy of automated immune agglutination assay was decreased in the regions of low and high ASO values. Availability, precision and accuracy of ASO measurement were improved by the automated analysis. However, the methods of ASO measurements were increased and varied by the automated assay. Therefore, it is necessary to standardize the automated ASO measurements. The limitation and the clinical significance of the automated immune agglutination assay of ASO have to be studied for practical use in the future.