TABLE 2.

Comparative specificities of the Pgp3 ELISA and commercial ELISAs

AssayNo. of samplesSpecificity (%) (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
    Pgp374096.1 (94.4 to 97.3)
    Ani Labsystems595b98.7 (97.3 to 99.4)−3.2 (−5.2 to −1.2)0.001
    SeroCT74096.9 (95.4 to 97.9)−0.8 (−2.7 to 1.1)0.45
    Medac74095.8 (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
    Pgp372297.6 (96.2 to 98.6)
    Ani Labsystems580b99.0 (97.7 to 99.6)−1.6 (−3.3 to 0.2)0.08
    SeroCT72297.2 (95.7 to 98.2)0.4 (−1.3 to 2.1)0.73
    Medac72296.0 (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.