Table 6:
Sensitivity and specificity of Xpert assay compared to AFB Results.
AFB smear Results
Total
AFB Positive
AFB Negative
Xpert
assay result
MTB detected
70
258
328
PPV =21.3%
MTB not detected
12
1099
1111
NPV =98.9%
Total
82
1357
1439
Sensitivity = 85.4%
Specificity= 81%
Note: - PPV: Positive Predictive Value, NPV: Negative Predictive Value