Table 3.
Total PSA and %fPSA measurements between the Roche and other assays using the Passing-Bablok regression and Bland-Altman analysis
| Assay | Mean ± SD | Passing-Bablok analysis |
Bland-Altman analysis | |||
|---|---|---|---|---|---|---|
| Slope (95% CI) | Intercept (95% CI) | Pearson’s correlation coefficient (r2) | Relative bias (mean ± 1.96SD), % | |||
| tPSA (ng/ml) | Beckman | 6.45 ± 8.45 | 0.78 (0.77–0.80) | 0.17 (0.15–0.19) | 0.99 | −20.65 ± 10.82 |
| Diasorin | 7.79 ± 11.17 | 1.00 (0.94–1.05) | −0.32 (−0.37 to 0.26) | 0.97 | −6.13 ± 21.89 | |
| Brahms | 8.75 ± 10.94 | 1.04 (1.00–1.08) | 0.36 (0.32–0.40) | 0.98 | 9.56 ± 18.93 | |
| Abbott | 6.77 ± 8.34 | 0.89 (0.88–0.91) | −0.14 (−0.16 to 0.12) | 0.99 | −15.15 ± 12.74 | |
| Roche a | 8.03 ± 10.76 | |||||
| %fPSA (%) | Beckman | 0.17 ± 0.07 | 1.11 (1.03–1.20) | −1.80 (−1.89 to 1.71) | 0.97 | −0.27 ± 17.74 |
| Diasorin | 0.18 ± 0.08 | 1.17 (1.01–1.33) | −1.96 (−2.12 to 1.80) | 0.92 | 2.3 ± 27.87 | |
| Brahms | 0.19 ± 0.09 | 1.25 (1.12–1.38) | −2.15 (−2.28 to 2.02) | 0.96 | 10.62 ± 21.03 | |
| Abbott | 0.20 ± 0.09 | 1.30 (1.11–1.49) | −1.96 (−2.15 to 1.77) | 0.93 | 15.74 ± 24.96 | |
| Roche a | 0.17 ± 0.06 | |||||
CI = confidence interval; %fPSA = free to total prostate-specific antigen ratio; PSA = prostate-specific antigen; SD = standard deviation; tPSA = total prostate-specific antigen.
a
Reference assay.