This study evaluated the performance of the Xpert MTB/RIF Ultra assay (Xpert Ultra) to detect smear-negative pulmonary tuberculosis (PTB). Xpert Ultra assay was prospectively performed using bronchial washing fluid (BWF) in comparison to COBAS TaqMan MTB (COBAS) assay and mycobacterial culture. Of the 165 enrolled participants, 27 (16.4%) had PTB based on composite reference standard and 16 (9.7%) had culture-confirmed PTB. By the composite reference standard of PTB, the sensitivity of Xpert Ultra (63.0, 95% confidence interval, CI, 42.4–80.6%) was higher than the COBAS assay (25.9%, P = 0.006), BWF-culture (33.3%, P = 0.029) and sputum-culture (37.0%, P = 0.057). Meanwhile, the specificity of Xpert Ultra was 99.3% which was slightly lower than the 100.0% specificity of the COBAS assay (P = 1.000) and cultures (P = 1.000). Against the reference standard of culture-confirmed PTB, Xpert Ultra also had a higher sensitivity (62.5, 95% CI, 35.4–84.8%) than the COBAS assay (31.3%, P = 0.077) and was similar to BWF-culture (56.3%, P = 0.719) and sputum-culture (62.5%, P = 1.000). However, one subject with previously treated old PTB had a false-positive result on the Xpert Ultra assay. This prospective study showed Xpert Ultra assay using BWF had better sensitivity than COBAS assay and mycobacterial cultures but could represent a false positive in patients with inactive old PTB.

这项研究评估了Xpert MTB / RIF Ultra检测（Xpert Ultra）检测涂片阴性肺结核（PTB）的性能。与COBAS TaqMan MTB（COBAS）分析和分枝杆菌培养相比，使用支气管冲洗液（BWF）前瞻性进行Xpert Ultra分析。在165名参加研究的参与者中，有27名（16.4％）具有基于综合参考标准的PTB，而16名（9.7％）具有文化确认的PTB。根据PTB的复合参考标准，Xpert Ultra的灵敏度（63.0，95％置信区间，CI，42.4–80.6％）高于COBAS分析（25.9％，P = 0.006），BWF文化（33.3％， P = 0.029）和痰培养（37.0％， P= 0.057）。同时，Xpert Ultra的特异性为99.3％，略低于COBAS分析的100.0％的特异性（P = 1.000）和文化（P= 1.000）。相对于培养物确证的PTB参照标准，Xpert Ultra还具有比COBAS分析（31.3％，32.5％，95％CI，35.4–84.8％）更高的灵敏度。P = 0.077），与BWF文化相似（56.3％， P = 0.719）和痰培养（62.5％， P= 1.000）。但是，一名先前治疗过的旧PTB的受试者在Xpert Ultra检测中的结果为假阳性。这项前瞻性研究表明，使用BWF的Xpert Ultra检测比COBAS检测和分枝杆菌培养具有更高的灵敏度，但对于无活动性老PTB的患者可能表示假阳性。