TABLE 2.
Comparative specificities of the Pgp3 ELISA and commercial ELISAs
| Assay | No. of samples | Specificity (%) (95% CI) | Difference in specificity between the Pgp3 assay and the commercial assaya (%) (95% CI) | McNemar's P value |
|---|---|---|---|---|
| Before exclusion of 18 sera positive for C. trachomatis by MIF | ||||
| Pgp3 | 740 | 96.1 (94.4 to 97.3) | ||
| Ani Labsystems | 595b | 98.7 (97.3 to 99.4) | −3.2 (−5.2 to −1.2) | 0.001 |
| SeroCT | 740 | 96.9 (95.4 to 97.9) | −0.8 (−2.7 to 1.1) | 0.45 |
| Medac | 740 | 95.8 (94.1 to 97.1) | 0.3 (−1.8 to 2.3) | 0.89 |
| After exclusion of 18 sera positive for C. trachomatis by MIF | ||||
| Pgp3 | 722 | 97.6 (96.2 to 98.6) | ||
| Ani Labsystems | 580b | 99.0 (97.7 to 99.6) | −1.6 (−3.3 to 0.2) | 0.08 |
| SeroCT | 722 | 97.2 (95.7 to 98.2) | 0.4 (−1.3 to 2.1) | 0.73 |
| Medac | 722 | 96.0 (94.3 to 97.2) | 1.7 (−0.2 to 3.6) | 0.09 |
a
The specificity of the commercial assay was subtracted from the specificity of the Pgp3 assay.
b
HPA pediatric serum samples had insufficient volume available for the Ani Labsystems assay.