Nucleic acid amplification tests reduce delayed diagnosis and misdiagnosis of pulmonary tuberculosis.

The clinical impact of nucleic acid amplification (NAA) tests on reducing delayed diagnosis and misdiagnosis of pulmonary TB (PTB) has rarely been investigated. PTB patients were classified into a frontline NAA group, an add-on NAA group, and a no NAA group. The outcomes of interest were the proportion of PTB case died before anti-TB treatment, the interval between sputum examination and initiation of treatment, and misdiagnosis of PTB. A total of 2192 PTB patients were enrolled, including 282 with frontline NAA, 717 with add-on NAA, and 1193 with no NAA tests. Patients with NAA tests had a lower death rate before treatment initiation compared to those without NAA tests (1.6% vs. 4.4%, p < 0.001) in all cases. Patients with frontline NAA compared to those with add-on NAA and those without NAA, had a shorter interval between sputum examination and treatment initiation in all cases (3 days vs. 6 days (p < 0.001), vs 18 days (p < 0.001)), and less misdiagnosis in smear-positive cases (1.8% vs. 5.6% (p = 0.039), vs 6.5% (p = 0.026)). In conclusion, NAA tests help prevent death before treatment initiation. Frontline NAA tests perform better than add-on NAA and no NAA in avoiding treatment delay in all cases, and misdiagnosis of PTB in smear-positive cases.