Table 4

Likelihood ratios of positive and negative test results, for different rheumatoid factor assays in rheumatoid arthritis

Positive testNegative test
TestLikelihood ratio95% Confidence intervalLikelihood ratio95% Confidence interval
Latex test (our laboratory)5.43.1 to 9.80.320.24 to 0.42
Immco IgM, IgG, and IgA RFs1.61.3 to 2.10.300.19 to 0.47
Sigma IgM RF4.12.6 to to 0.38
Diamedix IgM RF2.62.0 to to 0.29
IgM RF (our laboratory)3.12.1 to to 0.40
Inova IgA RF5.43.0 to 10.20.400.31 to 0.50
IgA RF (our laboratory)4.82.4 to 9.90.610.52 to 0.72