Xpert MTB/RIF Ultra outperformed the Xpert assay in tuberculosis lymphadenitis diagnosis: a prospective head-to-head cohort study

Objectives: Xpert Mycobacterium tuberculosis/rifampin (MTB/RIF) Ultra (Xpert-Ultra) has shown better sensitivity in comparison with Xpert MTB/RIF (Xpert) in extrapulmonary tuberculosis (TB), whereas the head-to-head comparison of these methods in TB lymphadenitis had barely been performed. Methods: Patients with undiagnosed lymphadenopathy were recruited prospectively and consecutively, and fine-needle aspiration ( FNA) biopsy or lymph node tissue was collected. The specimen was subjected to smear, culture, Xpert, and Xpert-Ultra assays. Culture and/or smear for acid-fast bacilli (AFB) or AFB observed on histopathology were performed as a reference. Results: A total of 106 participants were recruited, including 41 confirmed TB, 33 probable TB, and 32 non-TB lymphadenopathies. The head-to-head comparison for MTB detection showed that Xpert-Ultra produced the highest sensitivity when compared with smear, culture, and Xpert (75.7% vs 5.4 %, 13.5%, and 48.7%). When Xpert-Ultra outcomes were integrated for diagnosis, the percentage of confirmed TB lymphadenitis cases increased from 55.4% (41/74) to 85.1% (63/74). The sensitivities of Xpert-Ultra and Xpert on tissue were 73.6% (95% CI: 59.4-84.3) and 39.6% (95% CI: 26.8-54.0), respectively. The sensitivity of Xpert-Ultra on FNA samples (81.0%, 95% CI: 57.4-93.7) was higher than that of Xpert (71.4%, 95% CI: 47.7-87.8). Conclusion: Xpert-Ultra detected significantly more TB lymphadenitis cases than Xpert or culture. This superiority was particularly distinct using lymph node tissue than FNA detection. (c) 2022 The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Automated summary

Xpert-Ultra demonstrates significantly higher sensitivity in the detection of tuberculosis lymphadenitis, particularly in lymph node tissue.