TABLE 2.
Sensitivity, specificity, and positive and negative predictive values of different serological tests for diagnosis of Q fever
| Test | Form of disease | Titer | Sensitivity (%) | Specificity (%) | Positive predictive value (%) | Negative predictive value (%) | Reference |
|---|---|---|---|---|---|---|---|
| Microimmunofluorescence | Acute | Anti-phase II IgG, ≥1:200; anti-phase II IgM, ≥1:50 | 58.4 | 92.2 | NAa | 88–96.6 | 181 |
| Chronic | Anti-phase I IgG, ≥1:800 | 100 | NA | 98.6 | NA | 181 | |
| Anti-phase I IgG, ≥1:1,600 | NA | NA | 100 | NA | 181 | ||
| ELISA | Acute | Anti-phase II IgG, ≥1:1,024 | 80 | >99 | NA | NA | 191 |
| Anti-phase II IgM, ≥1:512 | 84 | ||||||
| Acute (screening) | Anti-phase II IgG, ≥1:128; anti-phase II IgM, ≥1:128 | NA | 97.3–98.7 | NA | NA | 191 | |
| Microagglutination | Acute | 1:64 | 81.6 | 98.6 | NA | NA | 123 |
a
NA, not available.