Table 2.
TB diagnostic tests for use at district hospitals and peripheral health facilities.
| Diagnostic Test | Advantages | Disadvantages |
|---|---|---|
| Sputum smear microscopy for AFB | Long experience, inexpensive, and uses light microscopy | Cumbersome for laboratory staff and patients |
| Identifies the most infectious patients | Does not identify drug resistance | |
| Used for follow-up of patients on treatment | Does not distinguish viable and nonviable AFB | |
| Does not distinguish MTB from non-tuberculous mycobacteria | ||
| Xpert MTB/RIF | Easy to use and rapid results in 2 h | Instruments and cartridges expensive |
| Identifies rifampicin resistance | High infrastructure and maintenance needs | |
| Chest radiograph | Long experience with use | No radiographic pattern absolutely diagnostic of TB |
| Atypical and normal radiographs with HIV advanced disease | ||
| Urine LAM | Inexpensive and easy to use at the bed side with test strip | For use in HIV-infected patients |
| Rapid results in 30 min | Sensitivity increases as CD4 cell counts decrease | |
| TB-LAMP | Simple to use, easy visual display and results in one hour | Does not identify drug resistance |
TB = tuberculosis; AFB = acid-fast bacilli; MTB = Mycobacterium tuberculosis; RIF = rifampicin; LAM = lipoarabinomannan; LAMP = loop-mediated isothermal amplification.