Objective: In settings of high HIV prevalence, tuberculosis control and patient management are hindered by lack of accurate, rapid tuberculosis diagnostic tests that can be performed at point-of-care. The Determine TB LAM Ag (TB LAM) test is a lateral flow immunochromatographic test for detection of mycobacterial lipoarabinomannan (LAM) in urine. Our objective was to determine sensitivity and specificity of the TB LAM test for tuberculosis diagnosis.
Design: Prospective diagnostic accuracy study.
Setting: Hospital and outpatient settings in Uganda and South Africa.
Participants: HIV-infected adults with tuberculosis symptoms and/or signs.
Methods: Participants provided a fresh urine specimen for TB LAM testing, blood for mycobacterial culture, and 2 respiratory specimens for smear microscopy and mycobacterial culture.
Main Outcome Measures: For the TB LAM test, sensitivity in participants with culture-positive tuberculosis and specificity in participants without tuberculosis.
Results: A total of 1013 participants were enrolled. Among culture-positive tuberculosis patients, the TB LAM test identified 136/367 (37.1%) overall and 116/196 (59.2%) in the group with CD4 ≤100 cells per cubic millimeter. The test was specific in 559/573 (97.6%) patients without tuberculosis. Sensitivity of the urine TB LAM test plus sputum smear microscopy was 197/367 (53.7%) overall and 133/196 (67.9%) among those with CD4 ≤100. CD4 ≤50 [adjusted odds ratio (AOR), 6.2; P < 0.001] or 51–100 (AOR, 7.1; P < 0.001), mycobacteremia (AOR, 6.1; P < 0.01) and hospitalization (AOR, 2.6; P = 0.03) were independently associated with a positive TB LAM test.
Conclusions: In HIV-positive adults with CD4 ≤100, the TB LAM urine test detected over half of culture-positive tuberculosis patients, in <30 minutes and without the need for equipment or reagents.
*Department of Medicine, Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda;
†Division of Medical Microbiology, University of Cape Town, Cape Town, South Africa and National Health Laboratory Service, South Africa;
‡Johns Hopkins University School of Medicine, Baltimore, MD;
§Department of Medicine, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD;
‖Department of Medical Microbiology, College of Health Sciences, Makerere University, Kampala, Uganda;
¶Division of Infectious Diseases, Department of Medicine, New Jersey Medical School, Newark, NJ; and
#Department of Medicine, Boston Medical Center, Boston University, Boston, MA.
Correspondence to: Susan E. Dorman, MD, Center for Tuberculosis Research, Department of Medicine, Johns Hopkins University, CRB2 Room 1M-12, 1550 Orleans Street, Baltimore, MD 21231 (e-mail: firstname.lastname@example.org).
Supported by federal funds from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and Human Services, under contract No. HHSN2722000900050C, “TB Clinical Diagnostics Research Consortium.” Additional support was provided by NIH K23AI089259 to M.S.
ClinicalTrials.gov: Nos. NCT01525134 and NCT01693224.
Presented in part at the 19th Conference on Retroviruses and Opportunistic Infections, March 5–8, 2012, Seattle, WA.
The authors have no conflicts of interest to disclose.
L.N. and V.M.M. contributed equally to this work. L.N. and V.M.M.: data collection, data analysis, data interpretation, and report writing; Y.C.M., M.P.N., D.A., J.J.E., and S.E.D.: study design, data analysis, data interpretation, and report writing; M.H. and D.T.A.: study design, data collection, and data interpretation; W.Z., W.S., and O.M.: data collection, data analysis, and data interpretation; B.A.S.N. and M.S.: data analysis, data interpretation, and report writing; M.L.J.: data collection, data interpretation, and report writing.
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Received November 22, 2013
Accepted January 31, 2014