Table 3. Comparison of CD4 T-cell counts between Pima CD4 and FACSCount.
| All | HIV+ | Low CD4 | Medium CD4 | High CD4 | |
| Intercept (95% CI) (cells/mm3) | 7 (4 to 20) | 12 (5 to 25) | 6 (−1 to 15) | 4 (−79 to 64) | −85 (−153 to −17) |
| Slope (95% CI) | 0.90 (0.87 to 0.94) | 0.87 (0.84 to 0.92) | 1.02 (0.86 to 1.13) | 0.96 (0.76 to 1.19) | 1.00 (0.91 to 1.09) |
| Concordance ρc (95% CI) | 0.98 (0.97 to 0.98) | 0.96 (0.95 to 0.97) | 0.93 (0.87 to 0.96) | 0.81 (0.67 to 0.90) | 0.93 (0.89 to 0.96) |
| Pearson ρ | 0.98 | 0.98 | 0.93 | 0.83 | 0.96 |
| Accuracy Cb | 0.99 | 0.98 | 0.99 | 0.98 | 0.97 |
| Bias (LOA) (cells/mm3) | −30 (−160 to 101) | −29 (−149 to 92) | 6 (−39 to 51) | −18 (−117 to 81) | −65 (−224 to 93) |
| Relative bias (LOA) | −3.5% (−41.0 to 33.9) | −3.4% (−43.1 to 36.2) | 7.3% (−44.4 to 59.0) | −5.2% (−34.4 to 23.9) | −9.7% (−32.7 to 13.3) |
| Mean Similarity (95% CI) | 99.3% (97.3 to 101.3) | 99.4% (97.2 to 101.7) | 106.0% (100.2 to 111.8) | 97.9% (95.7 to 100.2) | 95.7% (94.1 to 97.2) |
| Relative SD | 11.2% | 11.9% | 15.9% | 7.1% | 5.7% |
95% CI means 95% of Confidence Interval; Low means CD4 lower than 200 cells/mm3; Medium means CD4 between 200 and 500 cells/mm3; High means CD4 greater than 500 cells/mm3; HIV+ = HIV-infected patients, LOA = limits of agreement, SD = standard deviation.