TABLE 3.
Diagnostic accuracy parameters for the IDEIA Norovirus kit
| Sample source (n) | Diagnostic accuracy (95% CI) |
% Overall agreement | |||
|---|---|---|---|---|---|
| Sensitivity | Specificity | PPV | NPV | ||
| All samples (557) | 57.6 (55.0-59.6) | 91.9 (87.9-94.8) | 91.5 (87.2-94.6) | 59.0 (56.4-60.9) | 71.3 |
| Outbreaksa,b (102) | 58.7 (52.6-61.6) | 88.9 (72.2-97.0) | 93.6 (84.0-98.3) | 43.6 (35.4-47.6) | 66.7 |
| Sporadic cases (136) | 59.0 (50.6-64.0) | 93.3 (86.5-97.4) | 87.8 (75.3-95.2) | 73.7 (68.3-76.9) | 77.9 |
| Outbreaksb with indicated no. of samples collected | |||||
| 3 (46) | 44.1 (34.3-46.9) | 100.0 (71.8-100) | 93.8 (72.9-99.7) | 38.7 (27.9-41.8) | 57.4 |
| 4 (27) | 63.2 (47.9-68.1) | 100.0 (62.8-100.0) | 92.3 (70.0-99.6) | 53.3 (34.0-59.6) | 71.4 |
| 5 (17) | 76.9c (64.6-89.0) | 100 (45.4-100.0) | 83.3 (70.0-96.4) | 40.0 (7.9-71.3) | 76.4 |
| >5 (12) | 77.8c (55.8-88.3) | 100.0 (38.3-100.0) | 100.0 (59.6-97.9) | 60.0 (20.5-78.9) | 83.3 |
a
Outbreaks include three or more samples.
b
An outbreak was considered positive if two or more samples were positive.
c
Significantly different from outbreaks in which only three samples were collected (P < 0.05).