The TB-LAMP assay is designed to detect MTBC directly from sputum specimens. This is a manual assay that provides results in less than 1 hour, does not require sophisticated instrumentation and can be used at the peripheral health centre level, given biosafety requirements similar to those for sputum-smear microscopy. TB-LAMP does not detect resistance to anti-TB drugs. For the detection of TB in adults with signs and symptoms consistent with pulmonary TB, TB-LAMP has demonstrated a sensitivity of 0.78% (95% credible interval [CrI]: 0.71–0.83%) and a specificity of 0.98% (95% CrI: 0.96–0.99%) as compared with a microbiological reference standard.
WHO has made the following recommendations (5):¹⁴
- TB-LAMP may be used as a replacement test for sputum-smear microscopy for diagnosing pulmonary TB in adults with signs and symptoms consistent with TB.
- TB-LAMP may be used as a follow-on test to smear microscopy in adults with signs and symptoms consistent with pulmonary TB, especially when further testing of sputum-smear-negative specimens is necessary.
Notes:
- Because TB-LAMP does not provide any information on RIF resistance, TB-LAMP should not replace the use of rapid molecular tests that detect both MTBC and RIF resistance, especially among populations at risk of MDR-TB.
- TB-LAMP should also not replace the use of rapid molecular tests that have a higher sensitivity for the detection of TB among PLHIV who have signs and symptoms consistent with TB.
¹² See https://www.finddx.org/wp-content/uploads/2019/08/FIND_cDST_WHO_Supplement.xlsx
¹³ See https://apps.who.int/iris/bitstream/handle/10665/342331/9789240029415-eng.pdf