Table 1.
Diagnostic accuracy of the io® CT assay when compared with the reference standarda.
| All | Symptomatic | Asymptomatic | Symptomatic vs asymptomatic p-valueb |
“Fresh” | “Frozen” | “Fresh” vs “frozen” p-valueb |
|
|---|---|---|---|---|---|---|---|
| Prevalence | 7.2 (5.4–9.3) (51/709) |
11 (6.0–18.1) (13/118) |
6.4 (4.6–8.7) (38/591) |
0.106 | 9.3 (6.1–13.3) (26/281) |
5.8 (3.8–8.5) (25/428) |
0.111 |
| Sensitivity | 96.1 (86.5–99.5) (49/51) |
100.0 (75.3–100.0) (13/13) |
94.7 (82.3–99.4) (36/38) |
0.906 | 96.2 (80.4–99.9) (25/26) |
96.0 (79.6–99.9) (24/25) |
0.997 |
| Specificity | 97.7 (96.3–98.7) (643/658) |
98.1 (93.3–99.8) (103/105) |
97.6 (96.0–98.7) (540/553) |
0.976 | 96.5 (93.4–98.4) (246/255) |
98.5 (96.8–99.5) (397/403) |
0.854 |
| PPV | 76.6 (64.3–86.2) (49/64) |
86.7 (59.5–98.3) (13/15) |
73.5 (58.9–85.1) (36/49) |
0.706 | 73.5 (55.6–87.1) (25/34) |
80.0 (61.4–92.3) (24/30) |
0.824 |
| NPV | 99.7% (98.9–100.0) (643/645) |
100.0 (96.5–100.0) (103/103) |
99.6 (98.7–100.0) (540/542) |
0.981 | 99.6 (97.8–100.0) (246/247) |
99.7 (98.6–100.0) (397/398) |
0.989 |
CT, Chlamydia trachomatis; PPV, Positive Predictive Value; NPV, Negative Predictive Value.
a
Values are percentages (95% confidence intervals) (numbers).
b
Study prevalence of CT and performance characteristics (sensitivity, specificity, PPV and NPV) were compared between symptomatic and asymptomatic participants and between “fresh” and “frozen” samples using the Pearson Chi-squared test for comparing two proportions.