Evaluation of an automated chemiluminescent immunoassay for complexed PSA on the Bayer ACS:180 system.
Prostate-specific antigen (PSA), the most important tumor marker for the detection of prostate cancer, exists in serum in a free, uncomplexed form (free PSA [fPSA]), and as bound to protease inhibitors (mainly alpha1-antichymotrypsin [ACT]). The measurement of complexed PSA (cPSA) concentration in serum has been shown to have better sensitivity and specificity than serum total PSA concentration. A new chemiluminescent immunoassay for cPSA for use on the Bayer ACS:180 fully automated system (Bayer Corp, Tarrytown, NY) has been developed and evaluated. The precision of the new assay was <3.9% (within-run coefficient of variation [CV]) and <5.0% (total CV). The analytical sensitivity (95% upper limit of noise at zero calibrator) was <0.03 ng/mL. A comparison of the ACS:180 cPSA results with the cPSA concentrations calculated from the ACCESS (Beckman-Coulter) PSA and fPSA assays yielded the following regression equation: ACS:180 cPSA=0.93* (calculated ACCESS cPSA)+0.43, R=0.993, n=95. The mean dilution and spike recovery for five samples were both 98%. No interference was observed from hemoglobin, triglyceride, or bilirubin (NCCLS protocol). These results indicate that the ACS:180 cPSA assay is precise, and compares well with the calculated cPSA from ACCESS total and free-PSA results.
Datta
Pradip
P
Bayer Diagnostics, Tarrytown, New York 10951, USA. pradip.datta.b@bayer.com
Dasgupta
Amitava
A
D000937:Antigen-Antibody Reactions; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods*; D016014:Linear Models; D008163:Luminescent Measurements; D008297:Male; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000032:analysis*; D011485:Protein Binding; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D000514:alpha 1-Antichymotrypsin / Q000032:analysis
D000514:alpha 1-Antichymotrypsin; D017430:Prostate-Specific Antigen