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Updated: Mar 19, 2026

Diagnosing Pulmonary Tuberculosis with the Xpert MTB/RIF Test
Published on: April 9, 2012
Diagnostic accuracy of TB-LAMP and smear microscopy for pulmonary TB in active case finding
A Shimouchi1,2, R S Gopali1, B Maharjan3
1Japan Anti-Tuberculosis Association (JATA), Nepal Office, Kathmandu, Nepal.
Background:
In Nepal, most sputum tests are done with smear microscopy. However, in order to increase case detection by active case finding (ACF), more sensitive bacteriological test should be used.
Methods:
Presumptive TB cases aged five and over detected by symptomatic screening and X-ray screening for pulmonary TB were included in the study. Smear microscopy, loop-mediated isothermal-amplification for TB (TB-LAMP), and Xpert MTB/RIF (Xpert) were performed as part of routine TB diagnostic procedure in ACF. We compared the diagnostic accuracy of TB-LAMP and smear microscopy by using Xpert as the microbiological reference standard.
Results:
Among 653 samples, sensitivity, specificity, and kappa value of smear microscopy and TB-LAMP were 30.5% (95% confidence interval [CI]: 21.6-41.1), 99.8% (95% CI: 99.0-99.9), 0.43 (95% CI: 0.36-0.49) and 72.0% (95% CI: 61.4-80.5), 99.7% (95% CI: 98.7-99.9), 0.80 (95% CI: 0.73-0.88), respectively. Sensitivity of TB-LAMP (72.0%) was 41.5% higher than that of smear microscopy (30.5%) (P < 0.01). Sensitivity of TB-LAMP and smear microscopy was high for multibacillary TB. Sensitivity of TB-LAMP was substantially higher than that of smear microscopy for paucibacillary TB.
Conclusion:
Sensitivity of TB-LAMP was much higher than that of smear microscopy in ACF. TB-LAMP is recommended to replace smear microscopy in ACF to increase the detection of bacteriologically confirmed pulmonary TB.
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