TABLE 3.
Comparison of LCx assay, culture, and microscopy results with clinical diagnosis of tuberculosis
| Method and result (no. of samples) | No. of specimensa
|
Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) | |
|---|---|---|---|---|---|---|
| TB+ | TB− | |||||
| LCx assay | ||||||
| Positive (59) | 56 | 3b | 78 | 100 | 95 | 98 |
| Negative (678) | 16 | 662c | ||||
| Culture | ||||||
| Positive (61) | 61 | 0 | 85 | 100 | 100 | 98 |
| Negative (676) | 11 | 665c | ||||
| Microscopy | ||||||
| Positive (55) | 48 | 7d | 67 | 99 | 87 | 97 |
| Negative (682) | 24 | 658 | ||||
a
TB+, tuberculosis positive (total n = 72); TB−, tuberculosis negative (total n = 665).
b
One sample was negative when reassayed.
c
Including 10 samples positive for NTM.
d
Seven specimens were culture positive for NTM and LCx assay negative.