Between-assay correlations of measurement results for patient samples
| Analyte | Assay pair (x–y) | Slope | Intercept |
|---|---|---|---|
| Alpha-fetoprotein | Roche-Abbott | 0.8988 (0.8808 to 0.9135) | 1.7460 (0.3642 to 3.4328) |
| Roche-Siemens | 0.8924 (0.8776 to 0.9084) | 0.2542 (–0.9436 to 0.9050) | |
| Roche-Beckman | 0.9945 (0.9780 to 1.0098) | –0.0410 (–1.4764 to 0.5896) | |
| Abbott-Siemens | 0.9983 (0.9769 to 1.0179) | –1.1876 (–3.2560 to 0.0755) | |
| Abbott-Beckman | 1.1246 (1.1004 to 1.1506) | –2.1669 (–5.7047 to –0.2924) | |
| Siemens-Beckman | 1.1119 (1.0941 to 1.1374) | –0.6813 (–1.8866 to 0.1566) | |
| Carcinoembryonic antigen | Roche-Abbott | 1.0869 (1.0193 to 1.1582) | –1.0863 (–2.9313 to –0.2211) |
| Roche-Siemens | 0.7309 (0.6847 to 0.7937) | –0.6278 (–2.3317 to 0.1883) | |
| Roche-Beckman | 1.1696 (1.0833 to 1.2676) | –1.1795 (–3.7368 to 0.0173) | |
| Abbott-Siemens | 0.6548 (0.5783 to 0.7256) | 0.3653 (–0.4564 to 1.6287) | |
| Abbott-Beckman | 1.1038 (1.0091 to 1.2507) | –0.3280 (–2.2638 to 0.8486) | |
| Siemens-Beckman | 1.6587 (1.5705 to 1.7286) | –0.7319 (–1.5417 to 0.2363) | |
| Prostate-specific antigen | Roche-Abbott | 0.9324 (0.9115 to 0.9495) | 0.0517 (–0.1001 to 0.2945) |
| Roche-Siemens | 0.7906 (0.7659 to 0.8165) | 0.0306 (–0.3014 to 0.2181) | |
| Roche-Beckman | 1.1765 (1.1459 to 1.2034) | –0.0687 (–0.3715 to 0.2397) | |
| Abbott-Siemens | 0.8465 (0.8167 to 0.8685) | –0.0983 (–0.3507 to 0.2197) | |
| Abbott-Beckman | 1.2535 (1.2206 to 1.2793) | –0.2107 (–0.4366 to 0.1923) | |
| Siemens-Beckman | 1.4798 (1.4378 to 1.5259) | –0.0133 (–0.3760 to 0.4964) |
Values are presented as Pearson correlation coefficients (95% confidence interval). The instruments used were from Abbott Laboratories (Abbott Park, IL, USA), Beckman Coulter Inc. (Brea, CA, USA), Roche Diagnostics (Mannheim, Germany), and Siemens Healthineers (Erlangen, Germany)