title: Value of urine lipoarabinomannan grade and second test for optimizing clinic-based screening for HIV-associated pulmonary tuberculosis.
abstract: BACKGROUND
  We assessed the role of urine lipoarabinomannan (LAM) grade and a second LAM test for HIV-associated pulmonary tuberculosis (TB) screening in outpatient clinics in South Africa.
  
  
  METHODS
  We enrolled newly diagnosed HIV-infected adults (≥18 years) at 4 clinics, excluding those on TB therapy. Participants provided sputum for acid-fast bacilli (AFB) microscopy and culture. Nurses conducted 2 rapid urine LAM tests at the point-of-care and graded positive results from low (faint) to high (5+). Culture-confirmed pulmonary TB was the gold standard. We used area under receiver operating curves (AUROC) to compare screening strategies.
  
  
  RESULTS
  Among 320 HIV-infected adults, median CD4 was 248 cells per cubic millimeter (interquartile range, 107-379/mm); 54 (17%) were TB culture positive. Fifty-two (16%) of all participants were LAM positive by either test; correlation between LAM tests was high. Among 10 "faint" positive results, 2 (20%) had culture-positive TB. Using ≥1+ LAM grade as positive, 1 LAM test had sensitivity of 41% [95% confidence interval (CI): 28% to 55%] and specificity of 92% (95% CI: 88% to 95%). A 2 LAM test strategy had a sensitivity of 43% (95% CI: 29% to 57%). One LAM test ≥1+ grade (AUROC = 0.66; 95% CI: 0.60 to 0.73) was significantly better than sputum AFB alone. The optimal strategy was sequentially performing 1 LAM test followed by sputum AFB if LAM grade <1+ (AUROC = 0.70; 95% CI: 0.63 to 0.77), which had sensitivity of 48% (95% CI: 34% to 62%) and specificity of 91% (95% CI: 87% to 94%).
  
  
  CONCLUSIONS
  In this clinic-based study, "faint" line was a false-positive second urine LAM test added no value, and an optimal screening strategy was 1 LAM test followed by sputum AFB microscopy for urine LAM-negative people.
authors.affiliation: *Department of Medicine, Medical Practice Evaluation Center, Massachusetts General Hospital, Boston, MA; †Department of Medicine, Divisions of Infectious Diseases, Massachusetts General Hospital, Boston, MA; ‡Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; §General Internal Medicine, Department of Medicine, Massachusetts General Hospital, Boston, MA; ‖Department of Orthopedic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; ¶Boston University School of Public Health, Boston, MA; #Department of Medicine, McCord Hospital, Durban, South Africa; and **Department of Medicine, St. Mary's Hospital, Durban, South Africa.
authors.forename: Paul K
authors.initials: PK
authors.lastname: Drain
authors.forename: Elena
authors.initials: E
authors.lastname: Losina
authors.forename: Sharon M
authors.initials: SM
authors.lastname: Coleman
authors.forename: Janet
authors.initials: J
authors.lastname: Giddy
authors.forename: Douglas
authors.initials: D
authors.lastname: Ross
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Katz
authors.forename: Ingrid V
authors.initials: IV
authors.lastname: Bassett
mesh_terms: D017088:AIDS-Related Opportunistic Infections / Q000175:diagnosis*; D000328:Adult; D003955:Diagnostic Tests, Routine / Q000379:methods*; D005260:Female; D015658:HIV Infections / Q000150:complications*; D006801:Humans; D008070:Lipopolysaccharides / Q000652:urine*; D008297:Male; D008403:Mass Screening / Q000379:methods*; D019095:Point-of-Care Systems; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013019:South Africa; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D008070:Lipopolysaccharides; C050016:lipoarabinomannan