Likelihood ratios of positive and negative test results, for different rheumatoid factor assays in rheumatoid arthritis
| Positive test | Negative test | |||
|---|---|---|---|---|
| Test | Likelihood ratio | 95% Confidence interval | Likelihood ratio | 95% Confidence interval |
| Latex test (our laboratory) | 5.4 | 3.1 to 9.8 | 0.32 | 0.24 to 0.42 |
| Immco IgM, IgG, and IgA RFs | 1.6 | 1.3 to 2.1 | 0.30 | 0.19 to 0.47 |
| Sigma IgM RF | 4.1 | 2.6 to 6.8 | 0.28 | 0.20 to 0.38 |
| Diamedix IgM RF | 2.6 | 2.0 to 3.7 | 0.18 | 0.12 to 0.29 |
| IgM RF (our laboratory) | 3.1 | 2.1 to 4.7 | 0.28 | 0.20 to 0.40 |
| Inova IgA RF | 5.4 | 3.0 to 10.2 | 0.40 | 0.31 to 0.50 |
| IgA RF (our laboratory) | 4.8 | 2.4 to 9.9 | 0.61 | 0.52 to 0.72 |