Standardized method comparison for ACS : 180 plus and Immulite sensitive PSA (sPSA) measurement methods

The aim of this study was to compare two immunoassay measurement methods, the ACS: 180 Plus (Chiron Diagnostics) kit and the Immulite sPSA (DPC) kit. Method comparison analysis was performed according to EP9-A; approved guideline of NCCLS 51. Serum samples having a wide range of total prostate-specific antigen (PSA) concentrations were evaluated in split-sample analysis. F-test, t-test analysis and regression statistics were performed. In Deming regression analysis the coefficients were as follows; the slope=0.967; y-intercept=-0.148, r=0.989. An acceptable bias was seen since the systematical error was calculated to have a value less than the total allowable error calculated from biological variations. Nonparametric evaluation of the area under ROC curves for ACS: 180 Plus and Immulite sPSA were 0.997 and 0.987, respectively. Diagnostic accuracy was at the level of p=0.000 and no statistical difference was found between the two assay methods.