Table 2.
Validation of Xpert MTB/RIF Ultra using culture and/or routine PCR tests as a reference standard.
| Sample material | Sensitivity | Specificity | PPV | NPV | Accuracy |
|---|---|---|---|---|---|
| % (95% CI) TP/(TP + FN) |
% (95% CI) TN/(TN + FP) |
% TP/(TP + FP) |
% TN/(TN + FN) |
% (95% CI) (TP + TN)/(TP + FP + FN + FP) |
|
| All samples |
90 (56–100) 9/10 |
99 (93–100) 71/72 |
90 9/10 |
99 71/72 |
98 (91–100) 80/82 |
| Lymph node biopsy |
100 (3–100) 1/1 |
75 (19–99) 3/4 |
50 1/2 |
100 3/3 |
83 (6–100) 4/5 |
| Lymph node aspirate |
100 (40–100) 4/4 |
100 (72–100) 11/11 |
100 4/4 |
100 11/11 |
100 (78–100) 15/15 |
| Pus samples |
100 (16–100) 2/2 |
100 (77–100) 14/14 |
100 2/2 |
100 14/14 |
100 (79–100) 16/16 |
| Other biopsies |
100 (3–100) 1/1 |
100 (75–100) 13/13 |
100 1/1 |
100 13/13 |
100 (77–100) 14/14 |
| Fluid samples |
0 (0–98) 0/1 |
100 (88–100) 28/28 |
0 N/A |
97 28/29 |
97 (82–100) 28/29 |
| Gastrointestinal lavage |
100 (3–100) 1/1 |
100 (16–100) 2/2 |
100 1/1 |
100 2/2 |
100 (30–100) 3/3 |
95% confidence intervals for sensitivity, specificity and accuracy were calculated using the exact Clopper–Pearson method.
CI confidence interval, TP true positive, FN false negative, TN true negative, FP false positive.