TABLE 1.
Results for prospective specimens prior to resolution of discrepancies
| Target and specimen type | No. of samples with BD Max EBP result with reference to culture/EIA |
Total no. of samples | PPA (95% confidence interval) | P value for PPAa | NPA (95% confidence interval) | P value for NPAa | |||
|---|---|---|---|---|---|---|---|---|---|
| True positive | False negative | False positive | True negative | ||||||
| Campylobacter | |||||||||
| Total | 44 | 1 | 51 | 2,797 | 2,893 | 97.8 (88.4–99.6) | 98.2 (97.7–98.6) | ||
| Preserved | 24 | 1 | 21 | 1,681 | 1,727 | 96.0 (80.5–99.3) | 1.000 | 98.8 (98.1–99.2) | 0.010 |
| Unpreserved | 20 | 0 | 30 | 1,116 | 1,166 | 100 (83.9–100) | 97.4 (96.3–98.2) | ||
| Salmonella | |||||||||
| Total | 34 | 5 | 26 | 2,857 | 2,922 | 87.2 (73.3–94.4) | 99.1 (98.7–99.4) | ||
| Preserved | 16 | 3 | 15 | 1,721 | 1,755 | 84.2 (62.4–94.5) | 0.951 | 99.1 (98.6–99.5) | 0.950 |
| Unpreserved | 18 | 2 | 11 | 1,136 | 1,167 | 90.0 (69.9–97.2) | 99.0 (98.3–99.5) | ||
| Shigella | |||||||||
| Total | 24 | 0 | 10 | 2,889 | 2,923 | 100 (86.2–100) | 99.7 (99.4–99.8) | ||
| Preserved | 7 | 0 | 5 | 1,743 | 1,755 | 100 (64.6–100) | 1.000 | 99.7 (99.3–99.9) | 0.732 |
| Unpreserved | 17 | 0 | 5 | 1,146 | 1,168 | 100 (81.6–100) | 99.6 (99.0–99.8) | ||
| Shiga toxins | |||||||||
| Total | 8 | 2 | 17 | 2,347 | 2,374 | 80.0 (49.0–94.3) | 99.3 (98.9–99.6) | ||
| Preserved | 6 | 2 | 12 | 1,701 | 1,721 | 75.0 (40.9–92.9) | 1.000 | 99.3 (98.8–99.6) | 1.000 |
| Unpreserved | 2 | 0 | 5 | 646 | 653 | 100 (34.2–100) | 99.2(98.2–99.7) | ||
a
P value for testing of the significance of the difference between preserved and unpreserved specimens.