Diagnostic value of the urine lipoarabinomannan assay in HIV-positive, ambulatory patients with CD4 below 200 cells/μl in 2 low-resource settings: A prospective observational study.
Mathabire Rucker, SC
MetadataShow full item record
AbstractBACKGROUND: Current guidelines recommend the use of the lateral flow urine lipoarabinomannan assay (LAM) in HIV-positive, ambulatory patients with signs and symptoms of tuberculosis (TB) only if they are seriously ill or have CD4 count ≤ 100 cells/μl. We assessed the diagnostic yield of including LAM in TB diagnostic algorithms in HIV-positive, ambulatory patients with CD4 < 200 cells/μl, as well as the risk of mortality in LAM-positive patients who were not diagnosed using other diagnostic tools and not treated for TB. METHODS AND FINDINGS: We conducted a prospective observational study including HIV-positive adult patients with signs and symptoms of TB and CD4 < 200 cells/μl attending 6 health facilities in Malawi and Mozambique. Patients were included consecutively from 18 September 2015 to 27 October 2016 in Malawi and from 3 December 2014 to 22 August 2016 in Mozambique. All patients had a clinical exam and LAM, chest X-ray, sputum microscopy, and Xpert MTB/RIF assay (Xpert) requested. Culture in sputum was done for a subset of patients. The diagnostic yield was defined as the proportion of patients with a positive assay result among those with laboratory-confirmed TB. For the 456 patients included in the study, the median age was 36 years (IQR 31-43) and the median CD4 count was 50 cells/μl (IQR 21-108). Forty-five percent (205/456) of the patients had laboratory-confirmed TB. The diagnostic yields of LAM, microscopy, and Xpert were 82.4% (169/205), 33.7% (69/205), and 40.0% (84/205), respectively. In total, 50.2% (103/205) of the patients with laboratory-confirmed TB were diagnosed only through LAM. Overall, the use of LAM in diagnostic algorithms increased the yield of algorithms with microscopy and with Xpert by 38.0% (78/205) and 34.6% (71/205), respectively, and, specifically among patients with CD4 100-199 cells/μl, by 27.5% (14/51) and 29.4% (15/51), respectively. LAM-positive patients not diagnosed through other tools and not treated for TB had a significantly higher risk of mortality than LAM-positive patients who received treatment (adjusted risk ratio 2.57, 95% CI 1.27-5.19, p = 0.009). Although the TB diagnostic conditions in the study sites were similar to those in other resource-limited settings, the added value of LAM may depend on the availability of microscopy or Xpert results. CONCLUSIONS: LAM has diagnostic value for identifying TB in HIV-positive patients with signs and symptoms of TB and advanced immunodeficiency, including those with a CD4 count of 100-199 cells/μl. In this study, the use of LAM enabled the diagnosis of TB in half of the patients with confirmed TB disease; without LAM, these patients would have been missed. The rapid identification and treatment of TB enabled by LAM may decrease overall mortality risk for these patients.
PublisherPublic Library of Science
- Should Urine-LAM Tests Be Used in TB Symptomatic HIV-Positive Patients When No CD4 Count Is Available? A Prospective Observational Cohort Study From Malawi.
- Authors: Huerga H, Rucker SCM, Bastard M, Dimba A, Kamba C, Amoros I, Szumilin E
- Issue date: 2020 Jan 1
- Lateral flow urine lipoarabinomannan assay for detecting active tuberculosis in HIV-positive adults.
- Authors: Shah M, Hanrahan C, Wang ZY, Dendukuri N, Lawn SD, Denkinger CM, Steingart KR
- Issue date: 2016 May 10
- Diagnostic accuracy, incremental yield and prognostic value of Determine TB-LAM for routine diagnostic testing for tuberculosis in HIV-infected patients requiring acute hospital admission in South Africa: a prospective cohort.
- Authors: Lawn SD, Kerkhoff AD, Burton R, Schutz C, Boulle A, Vogt M, Gupta-Wright A, Nicol MP, Meintjes G
- Issue date: 2017 Mar 21
- Test characteristics and potential impact of the urine LAM lateral flow assay in HIV-infected outpatients under investigation for TB and able to self-expectorate sputum for diagnostic testing.
- Authors: Peter J, Theron G, Chanda D, Clowes P, Rachow A, Lesosky M, Hoelscher M, Mwaba P, Pym A, Dheda K, TB-NEAT team.
- Issue date: 2015 Jul 9
- Diagnostic accuracy of a low-cost, urine antigen, point-of-care screening assay for HIV-associated pulmonary tuberculosis before antiretroviral therapy: a descriptive study.
- Authors: Lawn SD, Kerkhoff AD, Vogt M, Wood R
- Issue date: 2012 Mar