Research Article
Clinical and Imaging Characteristics of Smear Negative Pulmonary Tuberculosis Patients: A Comparative Study
Table 5
Diagnostic accuracy of AFS smear microscopy and GeneXpert MTB/RTF assay among SNPTB and SPPTB patients, Addis Ababa, Ethiopia, 2021.
| Accuracy of AFS vs. GeneXpert compared to the gold standard detecting MTBC among PTB patients | GeneXpert (pooled) | LJ culture (gold standard) | LJ culture positive | LJ culture negative | Total | AFS (pooled) | LJ culture positive | LJ culture negative | Total | Positive | 30 | 19 | 49 | Positive | 38 | 2 | 40 | Negative | 12 | 48 | 60 | Negative | 29 | 40 | 69 | Total | 42 | 67 | 109 | Total | 67 | 42 | 109 | Accuracy parameters | | (95% conf. inter.) | (95% conf. inter.) | Sensitivity | 71.64% | 63.18% | 80.10% | Sensitivity | 56.72% | 47.41% | 66.02% | Specificity | 71.43% | 62.95% | 79.91% | Specificity | 95.24% | 91.24% | 99.24% | PPV | 80.00% | 72.49% | 87.51% | PPV | 95.00% | 90.91% | 99.09% | NPV | 61.22% | 52.08% | 70.37% | NPV | 57.97% | 48.70% | 67.24% | Prevalence | 61.47% | 52.33% | 70.60% | Prevalence | 61.47% | 52.33% | 70.60% |
| Accuracy of GeneXpert detecting MTBC among SPPTB patients vs. among SNPTB patients | GeneXpert | SPPTB | | SNPTB | LJ culture positive | LJ culture negative | Total | | LJ culture positive | LJ culture negative | Total | Positive | 37 | 2 | 39 | Positive | 11 | 10 | 21 | Negative | 1 | 0 | 1 | Negative | 18 | 30 | 48 | Total | 38 | 2 | 40 | Total | 29 | 40 | 69 | Accuracy parameters | (95% conf. inter.) | (95% conf. inter.) | Sensitivity | 97.37% | 92.41% | 102.33% | Sensitivity | 37.93% | 26.48% | 49.38% | Specificity | 0.00% | 0.00% | 0.00% | Specificity | 75.00% | 64.78% | 85.22% | PPV | 94.87% | 88.04% | 101.71% | PPV | | | 64.17% | NPV | 0.00% | 0.00% | 0.00% | NPV | 62.50% | 51.08% | 73.92% | Prevalence | 95.00% | 88.25% | 101.75% | Prevalence | 42.03% | 30.38% | 53.68% |
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SNPTB: smear negative pulmonary tuberculosis; SPPTB: smear positive pulmonary tuberculosis; PPV: positive predictive value; NPV: negative predictive value.
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