TABLE 2

Clinical performance of Cobas versus PIS by symptomatic status for C. trachomatisa

Sex, sample typeSymptom statusTotal% sensitivity (no. of samples positive/total no. tested)95% CI for sensitivity% specificity (no. of samples positive/total no. tested)95% CIPrevalence (%)PPV (%)NPV (%)
Women
    UrineSymptomatic1,44196.0 (119/124)90.9–98.399.8 (1,315/1,317)99.4–100.08.698.399.6
    Asymptomatic2,41895.2 (140/147)90.5–97.799.6 (2,262/2,271)99.2–99.86.194.099.7
    Overall3,85995.6 (259/271)92.4–97.499.7 (3,577/3,588)99.5–99.87.095.999.7
    CC vaginal swabSymptomatic711100.0 (63/63)94.3–100.099.2 (643/648)98.2–99.78.992.6100.0
    Asymptomatic1,22597.6 (83/85)91.8–99.499.0 (1,129/1,140)98.3–99.56.988.399.8
    Overall1,93698.6 (146/148)95.2–99.699.1 (1,772/1,788)98.6–99.47.690.199.9
    SC vaginal swabSymptomatic720100.0 (59/59)93.9–100.098.8 (653/661)97.6–99.48.288.1100.0
    Asymptomatic1,18698.4 (60/61)91.3–99.799.2 (1,116/1,125)98.5–99.65.187.099.9
    Overall1,90699.2 (119/120)95.4–99.999.0 (1,769/1,786)98.5–99.46.387.599.9
    PreservCytSymptomatic1,43895.1 (116/122)89.7–97.799.5 (1,309/1,316)98.9–99.78.594.399.5
    Asymptomatic2,41390.3 (131/145)84.4–94.299.7 (2,261/2,268)99.4–99.96.094.999.4
    Overall3,85192.5 (247/267)88.7–95.199.6 (3,570/3,584)99.3–99.86.994.699.4
    Endocervical swabSymptomatic1,43395.9 (116/121)90.7–98.299.1 (1,300/1,312)98.4–99.58.490.699.6
    Asymptomatic2,41091.1 (133/146)85.4–94.799.5 (2,253/2,264)99.1–99.76.192.499.4
Overall3,84393.3 (249/267)89.6–95.799.4 (3,553/3,576)99.0–99.66.991.599.5
Men, urineSymptomatic305100.0 (63/63)94.3–100.099.6 (241/242)97.7–99.920.798.4100.0
Asymptomatic887100.0 (55/55)93.5–100.099.8 (830/832)99.1–99.96.296.5100.0
Overall1,192100.0 (118/118)96.8–100.099.7 (1,071/1,074)99.2–99.99.997.5100.0
Overall16,58795.5 (1,138/1,191)94.2–96.699.5 (15,312/15,396)99.3–99.67.293.199.7
  • a CC, clinician collected; Cobas, Cobas CT/NG test for use on the Cobas 6800/8800 systems; NPV, negative predictive value; PIS, patient infected status; PPV, positive predictive value; PreservCyt, cervical sample collected in PreservCyt cytology medium; SC, self-collected.