title: Rapid Urine LAM Testing Improves Diagnosis of Expectorated Smear-Negative Pulmonary Tuberculosis in an HIV-endemic Region.
abstract: We sought to determine if urine lipoarabinomannan (LAM) would improve diagnosis of pulmonary TB. We enrolled consecutive adults presenting with ≥2 TB-related symptoms, obtained one induced sputum sample for smear microscopy (AFB) and mycobacterial culture, and performed urine LAM testing (Determine(TM) TB LAM, Alere). We used culture-confirmed pulmonary TB as the gold standard, and compared accuracy with area under receiver operating characteristic curves (AUROC). Among 90 participants, 82 of 88 tested (93%) were HIV-infected with a median CD4 168/mm(3) (IQR 89-256/mm(3)). Diagnostic sensitivities of urine LAM and sputum AFB were 42.1% (95% CI 29.1-55.9%) and 21.1% (95% CI 11.4-33.9%), and increased to 52.6% (95% CI 39.0-66.0%) when combined. Sensitivity of LAM increased significantly among participants with a lower Karnofsky Performance score, anemia, hypoalbuminemia, and higher C-reactive protein. Combining LAM with AFB had an AUROC = 0.68 (95% CI 0.59-0.77), significantly better than AFB alone (AUROC=0.58; 95% CI 0.51-0.64). The combination of LAM and AFB was significantly better than AFB alone among patients with Karnofsky Performance score ≤90, hemoglobin ≤10 g/dL, albumin ≤25 g/L, C-reactive protein ≥25 mg/L, or CD4 <200/mm(3). Urine LAM testing may be most beneficial among patients with functional impairment, elevated inflammatory markers, or greater immunosuppression.
authors: Departments of Global Health, Medicine, and Epidemiology, University of Washington, Seattle, WA, USA.|Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors: Paul K
authors: PK
authors: Drain
authors: Department of Virology, National Health Laboratory Service, Inkosi Albert Luthuli Central Hospital, Durban, South Africa.
authors: Lilishia
authors: L
authors: Gounder
authors: Division of Infectious Diseases, Department of Internal Medicine, Chris Hani Baragwanath Academic Hospital, University of the Witwatersrand, Johannesburg, South Africa.
authors: Faieza
authors: F
authors: Sahid
authors: Department of Infectious Diseases, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa.
authors: Mahomed-Yunus S
authors: MY
authors: Moosa
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000652:urine; D002097:C-Reactive Protein / Q000378:metabolism; D018791:CD4 Lymphocyte Count; D060085:Coinfection; D005260:Female; D006678:HIV / Q000502:physiology; D015658:HIV Infections / Q000175:diagnosis / Q000821:virology; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D017567:Karnofsky Performance Status; D008070:Lipopolysaccharides / Q000652:urine*; D008297:Male; D008853:Microscopy; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000502:physiology*; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D012709:Serum Albumin / Q000378:metabolism; D013019:South Africa; D013183:Sputum / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000382:microbiology / Q000652:urine*
chemical_list: D015415:Biomarkers; D006454:Hemoglobins; D008070:Lipopolysaccharides; D012709:Serum Albumin; C050016:lipoarabinomannan; D002097:C-Reactive Protein