title: Validation of the ALS assay in adult patients with culture confirmed pulmonary tuberculosis.
abstract: BACKGROUND
  We have earlier shown that Bacille Calmette-Guérin (BCG) vaccine-specific IgG Antibodies in Lymphocyte Supernatant (ALS) can be used for diagnosis of active tuberculosis (TB) in adults and children.
  
  
  RESULTS
  The ALS method was validated in a larger cohort (n = 212) of patients with suspicion of pulmonary TB using multiple antigens (BCG, LAM, TB15.3, TB51A, CFP10-ESAT6-A, CFP, CW) from Mycobacterium tuberculosis. The sensitivity and specificity of the ALS assay was calculated using non-TB patients as controls. The sensitivity and the specificity were highest with BCG vaccine (90% and 88% respectively) followed by LAM (89% and 87% respectively). Simultaneous assessment of multiple antigen-specific antibodies increased sensitivity (91%) and specificity (88%). Using higher lymphocyte count in smaller volume of culture media increased detection and reduced the assay duration to ∼30 hrs. Twenty one patients with clinical findings strongly suggestive of TB finally diagnosed as non-TB patients were positive by the ALS assay, of which 9 (43%) were positive for 7 antigens and 19 (90%) for at least 3 antigens.
  
  
  CONCLUSIONS
  Our findings show that simultaneous detection of antigens improves the diagnostic potential of the ALS assay; the modified method increases sensitivity and can provide results in <48 hours, and enable detection of some cases of pulmonary TB that are not detectable by standard methods.
authors.affiliation: International Centre for Diarrhoeal Diseases Research, Bangladesh, Dhaka, Bangladesh.
authors.forename: Rokeya Sultana
authors.initials: RS
authors.lastname: Rekha
authors.forename: S M Mostafa
authors.initials: SM
authors.lastname: Kamal
authors.forename: Peter
authors.initials: P
authors.lastname: Andersen
authors.forename: Zeaur
authors.initials: Z
authors.lastname: Rahim
authors.forename: Md Imranul
authors.initials: MI
authors.lastname: Hoq
authors.forename: Gul
authors.initials: G
authors.lastname: Ara
authors.forename: Jan
authors.initials: J
authors.lastname: Andersson
authors.forename: David
authors.initials: D
authors.lastname: Sack
authors.forename: Rubhana
authors.initials: R
authors.lastname: Raqib
mesh_terms: D000328:Adult; D000942:Antigens, Bacterial / Q000032:analysis; D000961:Antilymphocyte Serum; D001500:BCG Vaccine / Q000276:immunology; D016022:Case-Control Studies; D006801:Humans; D012680:Sensitivity and Specificity; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*
chemical_list: D000942:Antigens, Bacterial; D000961:Antilymphocyte Serum; D001500:BCG Vaccine