TABLE 5.
Comparative sensitivities, specificities, and Youden index for diagnosis of symptomatic laboratory-confirmed pertussisa
Method of diagnosis (cutoff) | % Sensitivity (95% CIc) | % Specificity (95% CI) | Youden index |
---|---|---|---|
ptxA-Pr PCR | 15.5 (10.4-20.6) | 97.3 (95.0-99.6) | 0.13 |
IS481 PCR | 44.0 (37.0-51.0) | 84.7 (79.6-89.8) | 0.29 |
Single serology (≥100) | 67.9 (61.3-74.5) | 90.1 (85.9-94.3) | 0.58 |
Paired serology (×2b) | 23.8 (17.8-29.8) | 83.8 (78.6-89.0) | 0.08 |
Combination of single serology (≥100 EU/ml) with: | |||
Paired serology (×2) | 85.7 (80.8-90.6) | 75.7 (69.7-81.7) | 0.61 |
PtxA Pr PCR | 77.4 (71.5-83.3) | 87.4 (82.7-92.1) | 0.65 |
IS481 PCR | 90.5 (86.4-94.6) | 77.5 (71.6-83.4) | 0.68 |
Subjects are contacts of infant pertussis cases for whom there is complete laboratory data (n = 195). Complete data include symptoms, serology, and PCR analysis (IS481 and ptx-Pr) at enrollment and symptoms and serology at follow-up visit 1 month later.
×2, twofold change in titer.
CI, confidence interval.