Table 6.
Performance of different assays in patients with influenza like illness
| pH1N1 ELISA | BD Directigen EZ Flu A + B | |||
|---|---|---|---|---|
| Positive | Negative | Positive | Negative | |
| Pandemic H1N1 (n = 91)a | 84 | 7 | 64 | 27 |
| Seasonal influenza A (n = 171)a | 0 | 171 | 123 | 48 |
| Non‐influenza A (n = 642)a | 2 | 640 | 1 | 641 |
| Sensitivity 1 (95% CI) | 92.3 (84.8–96.9) | 70.3 (59.8–79.5) | ||
| Sensitivity 2 (95% CI) | NA | 71.9 (64.5–78.5) | ||
| Specificity 1 (95% CI) | 100 (96.4–100) | NA | ||
| Specificity 2 (95% CI) | 99.7 (98.9–99.9) | 99.8 (99.1–99.9) | ||
| Predicted value | For 2009 pandemic H1N1 | For total influenza A | ||
| PPV, % (95% CI) | 99.1 (98.2–99.7) | 99.5 (97.1–99.9) | ||
| NPV, % (95% CI) | 97.7 (91.9–99.7) | 89.5 (87.1–91.7) | ||
NA, not applicable; NPV, negative predictive value; pH1N1, pandemic (H1N1) 2009; PPV, positive predictive value.
Sensitivity 1: sensitivity in pandemic H1N1 patients. Sensitivity 2: sensitivity in seasonal influenza A patients. Specificity 1: specificity in seasonal influenza A patients. Specificity 2: specificity in non‐influenza A patients.
aData are no. positive/no. negative.