Open AccessPerformance of Xpert MTB/RIF Ultra for diagnosis of pulmonary and extra-pulmonary tuberculosis, one year of use in a multi-centric hospital laboratory in Brussels, Belgium
Author(s) -
Leila Mekkaoui,
Marie Hallin,
Françoise Mouchet,
Marie-Christine Payen,
Evelyne Maillart,
Philippe Clevenbergh,
Aspasia Georgala,
Sigi Van den Wijngaert
Publication year - 2021
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0249734
Subject(s) - medicine , pulmonary tuberculosis , gold standard (test) , mycobacterium tuberculosis , tuberculosis , drug resistance , rifampicin , sputum , gastroenterology , pathology , microbiology and biotechnology , biology
Among the challenges in controlling tuberculosis, a rapid and accurate diagnostic test for the detection of Mycobacterium tuberculosis complex ( MTB c) and its resistance to first line therapies is crucial. We evaluated the performance of the Xpert MTB/RIF Ultra assay (Xpert Ultra) for the rapid detection of MTB c and rifampicin resistance (RR) in 1120 pulmonary and 461 extra-pulmonary clinical specimens and compared it with conventional phenotypic techniques. The Xpert Ultra assay detected MTB c in 223 (14.1%) samples with an overall sensitivity and specificity, using culture as the “gold standard”, of 91.1% (95% CI, 85.6–95.1) and 94.5% (95% CI, 93.1–95.6), respectively. The sensitivity of the Xpert Ultra test for smear-negative extra-pulmonary specimens was high (87.1%), even higher than with smear-negative pulmonary specimens (81.8%). But this enhanced sensitivity came with a low overall specificity of smear-negative extra-pulmonary specimens (66.7%). For 73 patients, 79/1423 (3.4%) negative mycobacterial culture samples were found to be positive with Xpert Ultra. Clinical data was necessary to correctly interpret potential false-positive results, especially trace-positive results. Sensitivity of the Xpert Ultra to detect RR compared to drug susceptibility testing was 100% (95% CI, 29.2–100) and specificity was 99.2% (95% CI, 95.8–100). We concluded that the Xpert Ultra test is able to provide a reliable TB diagnosis within a significantly shorter turnaround time than culture. This is especially true for paucibacillary samples such as smear-negative pulmonary specimens and extra-pulmonary specimens.