Open Peer Review Any reports and responses or comments on the article can be found at the end of the article. RESEARCH NOTE Performance of Lipoarabinomannan Assay using Cerebrospinal fluid for the diagnosis of Tuberculous meningitis among HIV patients [version 1; peer review: awaiting peer review] Richard Kwizera , Fiona V. Cresswell , Gerald Mugumya , Micheal Okirwoth , Enock Kagimu , Ananta S. Bangdiwala , Darlisha A. Williams , Joshua Rhein , David R. Boulware , David B. Meya 1,4,5 Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda Clinical Research Department, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK MRC-UVRI and LSHTM Uganda Research Unit, Entebbe, Uganda Department of Medicine, School of Medicine, College of Health Sciences, Makerere University, Kampala, Uganda Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, 55455, USA Abstract The diagnostic utility of the Background: Mycobacteria tuberculosis lipoarabinomannan (TB-LAM) antigen lateral flow assay on cerebrospinal fluid (CSF) for the diagnosis of tuberculous meningitis (TBM) has not been extensively studied and the few published studies have conflicting results. Lumbar CSF from 59 HIV-positive patients with suspected TBM Methods: was tested with TB-LAM and Xpert MTB/Rif Ultra. The diagnostic performance of CSF TB-LAM was compared to positive CSF Xpert MTB/Rif Ultra (definite TBM) and a composite reference of probable or definite TBM according to the uniform case definition. Of 59 subjects, 12 (20%) had definite TBM and five (9%) had Results: probable TBM. With reference to definite TBM, CSF TB-LAM assay had a diagnostic sensitivity of 33% and specificity of 96%. When compared to a composite reference of definite or probable TBM, the sensitivity was 24% and specificity was 95%. There were two false positive tests with TB-LAM (3+ grade). In-hospital mortality in CSF TB-LAM positive patients was 17% compared to 0% in those with definite TBM by Xpert MTB/Rif Ultra but negative LAM. Lumbar CSF TB-LAM has a poor performance in diagnosing Conclusions: TBM. Both urine TB-LAM and Xpert Ultra should be further investigated in the diagnosis of TBM. Keywords Tuberculous meningitis, extra-pulmonary TB, lipoarabinomannan, TB-LAM, Xpert MTB/Rif Ultra, HIV, Diagnostics, cerebrospinal fluid 1 1-3 4 1 1 5 1,5 1,5 5 1,4,5 1 2 3 4 5 Reviewer Status AWAITING PEER REVIEW 19 Aug 2019, :123 ( First published: 4 ) https://doi.org/10.12688/wellcomeopenres.15389.1 19 Aug 2019, :123 ( Latest published: 4 ) https://doi.org/10.12688/wellcomeopenres.15389.1 v1 Page 1 of 6 Wellcome Open Research 2019, 4:123 Last updated: 19 AUG 2019