Table 1 Summary of data for PCR and LJ culture.
From: Diagnosis of tuberculosis: the experience at a specialized diagnostic laboratory
PCR and LJ culture | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Â | Smear +ve | Smear -ve | Overall | ||||||
| Â | Culture +ve | Culture -ve | Total | Culture +ve | Culture -ve | Total | Culture +ve | Culture -ve | Total |
PCR +ve | 60(26.3) | 32(14.0) | 92(40.4) | 9(3.8) | 35(14.9) | 44(18.7) | 69(14.9) | 71(15.3) | 140(30.2) |
PCR -ve | 88(38.6) | 48(21.1) | 136(59.6) | 39(16.6) | 152(64.7) | 191(81.3) | 123(26.6) | 200(43.2) | 323(69.8) |
Total | 148(64.9) | 80(35.1) | 228(100) | 48(20.4) | 187(79.6) | 235(100) | 192(41.4) | 271(58.5) | 463(100) |
Analysis of data | |||||||||
| Â | value | 95% Confidence Interval | value | 95% Confidence Interval | value | 95% Confidence Interval | |||
Sensitivity | 0.40 | 0.32 to 0.49 | 0.19 | 0.089 to 0.32 | 0.36 | 0.29 to 0.43 | |||
Specificity | 0.60 | 0.48 to 0.71 | 0.81 | 0.75 to 0.86 | 0.74 | 0.68 to 0.79 | |||
PPV | 0.65 | 0.55 to 0.75 | 0.20 | 0.098 to 0.35 | 0.49 | 0.41 to 0.58 | |||
NPV | 0.35 | 0.27 to 0.44 | 0.79 | 0.73 to 0.85 | 0.62 | 0.56 to 0.67 | |||
Likelihood Ratio | 1.01 | Â | Â | 1.00 | Â | Â | 1.37 | Â | Â |