TABLE 2.

Comparison of HC2 CT/GC algorithm performance to culture and DFA and PCR adjudicated results

Site and comparison% Sensitivity95% CIf% Specificity% PPV% NPV
1 (Birmingham)a
HC2 vs. cultureb94.0 (78/83)0.865-0.98098.0 (386/394)90.7 (78/86)98.7 (386/391)
HC2 vs. adjudicated94.5 (86/91)0.876-0.982100 (386/386)100 (86/86)98.7 (386/391)
Culture vs. adjudicated91.2 (83/91)0.834-0.961100 (386/386)100 (83/83)98.0 (386/394)
2 (Baltimore)c
HC2 vs. cultured93.1 (27/29)0.772-0.99290.8 (148/163)64.3 (27/42)98.7 (148/150)
HC2 vs. adjudicated95.3 (41/43)0.842-0.99499.3 (148/149)97.6 (41/42)98.7 (148/150)
Culture vs. adjudicated67.4 (29/43)0.515-0.809100 (149/149)100 (29/29)91.4 (149/163)
Combined
HC2 vs. culturee93.8 (105/112)0.876-0.97595.9 (534/557)82.0 (105/128)98.7 (534/541)
HC2 vs. adjudicated94.8 (127/134)0.895-0.97999.8 (534/535)99.2 (127/128)98.7 (534/541)
Culture vs. adjudicated83.6 (112/134)0.762-0.894100 (535/535)100 (112/112)96.1 (535/557)
  • a A total of 483 specimens were received from the Birmingham site, and 6 of them were excluded from the data analysis due to inadequate specimen volume. Of these, one tested positive by culture for N. gonorrhoeae and one was positive for both C. trachomatis and N. gonorrhoeae by culture. For both CT-ID and GC-ID tests, 252 specimens were examined.

  • b McNemar's two-sided P value is 0.5791.

  • c A total of 201 specimens were received from the Baltimore site and 9 of them were excluded. Of these, 2 had inadequate specimen volume, 6 specimens did not have culture results for either C. trachomatis or N. gonorrhoeae available, and 1 specimen had toxic chlamydia culture result. For this site, 115 clinical specimens were tested by both CT-ID and GC-ID kits. One specimen was culture negative but DFA stain positive.

  • d McNemar's two-sided P value is 0.0036.

  • e McNemar's two-sided P value is 0.0062.

  • f CI, confidence intervals.