TABLE 1.
WHO-endorsed molecular tests for pulmonary TB detection and drug susceptibility testinga
| Technology | Year endorsed | Method principle | Intended use | Sensitivity (%)b | Specificity (%)b | Target setting of use | Turnaround time (h) | Amenable to rapid test-and-treat? | Reference for policy guidance |
|---|---|---|---|---|---|---|---|---|---|
| Xpert MTB/RIF | 2010 | qPCR | MTB diagnosis and RIF resistance detection | 85 (pooled), 96 (RIF resistance) | 99 (MTB detection) 98 (RIF resistance) | District or subdistrict laboratory | <2 | Yes, especially on Omni platform | WHO 2020 (21), WHO 2016 (84) |
| Xpert MTB/RIF ultra | 2017 | qPCR/melting temperature analysis (RIF resistance) | MTB diagnosis and RIF resistance detection | 90 (pooled), 94 (RIF resistance) | 96 (MTB detection), 98 (RIF resistance) | District or subdistrict laboratory | <2 | Yes, especially on Omni platform | WHO 2020 (21) |
| First-line probe assays (e.g., GenoType MTBDRplus and NIPRO) | 2008 | PCR, hybridization | Diagnosis of RIF and INH resistance | 98 (RIF resistance), 84 (INH resistance) | 99 (RIF resistance), >99 (INH resistance) | Reference laboratory | 5 | No | WHO 2008 (14) |
| Second-line probe assays (e.g., GenoType MTBDRsl) | 2016 | PCR, hybridization | Diagnosis of FLQ and SLID resistance | 86 (FLQ resistance), 87 (SLID resistance) | 99 (FLQ resistance), 99 (SLID resistance) | Reference laboratory | 5 | No | WHO 2016 (15) |
| Loopamp MTBC assay | 2016 | Loop-mediated isothermal amplification | MTB diagnosis | 78 (pooled) | 98 (MTB detection) | Peripheral laboratory | <2 | Yes | WHO 2016 (16) |
| Truenat MTB plus | 2020 | Micro RT-PCR | MTB diagnosis | 80 (pooled) | 96 (MTB detection) | Peripheral laboratory | <2 | Yes, on Truelab platform | WHO 2020 (21) |
| Truenat MTB-RIF Dx | 2020 | Micro RT-PCR | Diagnosis of RIF resistance | 84 (RIF resistance) | 97 (RIF resistance) | Peripheral laboratory | <2 | Yes, on Truelab platform | WHO 2020 (21) |
a
FLQ, fluoroquinolone; INH, isoniazid; LAMP, loop-mediated isothermal amplification; NAAT, nucleic acid amplification tests; RIF, rifampin; RT-PCR, reverse transcriptase PCR; SLID, second-line injectable drugs; SSM+/C−, sputum smear microscopy positive/culture positive; SSM−/C+, sputum smear microscopy negative/culture positive; WHO, World Health Organization.
b
Performance estimates have been retrieved from different studies and are not the result of head-to-head comparisons. Therefore, comparing performances between tests must be made with caution. All reported values are from the policy guidance document cited.