Xpert MTB/RIF assay for the diagnosis of extrapulmonary tuberculosis: a systematic review and meta-analysis

Abstract

Xpert MTB/RIF (Cepheid, Sunnyvale, CA, USA) is endorsed for the detection of pulmonary tuberculosis (TB). We performed a systematic review and meta-analysis to assess the accuracy of Xpert for the detection of extrapulmonary TB.We searched multiple databases to October 15, 2013. We determined the accuracy of Xpert compared with culture and a composite reference standard (CRS). We grouped data by sample type and performed meta-analyses using a bivariate random-effects model. We assessed sources of heterogeneity using metaregression for predefined covariates.We identified 18 studies involving 4461 samples. Sample processing varied greatly among the studies. Xpert sensitivity differed substantially between sample types. In lymph node tissues or aspirates, Xpert pooled sensitivity was 83.1% (95% CI 71.4-90.7%) versus culture and 81.2% (95% CI 72.4-87.7%) versus CRS. In cerebrospinal fluid, Xpert pooled sensitivity was 80.5% (95% CI 59.0-92.2%) against culture and 62.8% (95% CI 47.7-75.8%) against CRS. In pleural fluid, pooled sensitivity was 46.4% (95% CI 26.3-67.8%) against culture and 21.4% (95% CI 8.8-33.9%) against CRS. Xpert pooled specificity was consistently .98.7% against CRS across different sample types.Based on this systematic review, the World Health Organization now recommends Xpert over conventional tests for diagnosis of TB in lymph nodes and other tissues, and as the preferred initial test for diagnosis of TB meningitis. @ERSpublications Xpert MTB/RIF can improve the diagnosis of lymph node TB and TB meningitis

Diagnostic accuracy of Xpert MTB/RIF Ultra for tuberculous meningitis in HIV-infected adults: A prospective cohort study

“…Among participants without cryptococcal meningitis (who require large volume lumbar punctures for control of intracranial pressure), testing of at least 6 mL of CSF (median 10 mL [IQR [8][9][10][11][12]) was associated with a tuberculous meningitis diagnosis (19 [26%] of 73) compared with less than 6 mL (4 mL [3-5mL]; 3 [7%] of 43; p=0·014)].…”

“…5 In 2013, WHO endorsed the Xpert MTB/RIF assay (Cepheid, Sunnyvale, CA, USA) as the preferred initial test to investigate tuberculous meningitis after a systematic review of 13 studies. [6][7][8] The Xpert is cartridge-based fullyautomated PCR test. Of three large cohorts, the first reported 67% sensitivity using Xpert in microbiologically proven tuberculous meningitis in HIV-infected South Africans.…”

Xpert<SUP>®</SUP> MTB/RIF assay sensitivity with different methods of CSF processing for the diagnosis of TB meningitis

“…Previous studies of M. tuberculosis in sputum reveal a subpopulation of bacteria that do not grow in standard conditions but require an exogenous source of resuscitation-promoting factor (Rpf) for growth. 2 Rpf is a family of enzymes secreted by growing mycobacteria that have been implicated in the resuscitation and growth stimulation of dormant …”

“…Several studies have examined the accuracy of the Xpert assay on CSF, showing that while specificity is consistently very high, sensitivity values are heterogeneous and depend on sample size, tuberculosis (TB) prevalence and the test used as gold standard. [1][2][3][4] As a consequence, the World Health Organization (WHO) has endorsed using Xpert in preference to conventional microscopy as the initial diagnostic test for patients presumed to have TB meningitis, given the urgency of obtaining a rapid diagnosis.…”

Xpert MTB/RIF assay for the diagnosis of pulmonary tuberculosis in children: A systematic review and meta-analysis

“…Pooled sensitivities of Xpert using lymph-node tissue and cerebrospinal fluid are between 80% and 83%, but are only 46% using pleural fluid. 39 The ongoing rollout of Xpert in low-income and middle-income settings should increase access to much needed diagnostics for tuberculosis and rifampicin resistance in children.…”