title: Diagnostic value of two rapid immunochromatographic tests for suspected tuberculosis diagnosis in clinical practice.
abstract: OBJECTIVE
  To evaluate and compare the diagnostic value of two immunochromatographic tests for tuberculosis (ICT-TB) in clinical practice.
  
  
  METHODS
  The present extended cross-sectional study investigated suspected active TB patients at Maesai district hospital, and Lampang regional hospital between April 2009 and May 2010. Subjects underwent two commercial ICT-TB serum tests including: an endogenous ICT-TB, a local made test coated with 38 kD, 16 kD, and 6 kD antigens; and an exogenous ICT-TB, an imported test coated with 38 kD and lipoarabinomanan [LAM] antigens. All subjects received two months of follow up.
  
  
  RESULTS
  Of 401 patients, 146 (36.4%) had active TB, and 206 (51.4%) were HIVseropositive. An endogenous ICT-TB was superior to an exogenous ICT-TB in all diagnostic values measured except for specificity. In all patients, sensitivity was low, 35.6% (95% CI: 30.9-40.3) in an endogenous ICT-TB vs. 13.7% (95% CI: 10.3-17.1) in an exogenous ICT-TB. The specificity was high and equivalent in both tests, 93.7% (95%CI: 91.4-96.1). Higher diagnostic values were found among human immunodeficiency virus (HIV) seronegatives than in HIV seropositives when unadjusted for CD4+ cell count level. The likelihood ratios (LHR) were higher in patients with CD4+ cell count over 200 cells/microL than for the HIV seronegative group (LHR+ 7.6 vs. 4.8 in an endogenous ICT-TB, and 2.5 vs. 1.9 in an exogenous ICT-TB).
  
  
  CONCLUSIONS
  For the present study setting, an endogenous ICT-TB can be a meaningful tool for first-line testing to rule in TB suspected cases. Subgroups of HIV seronegative and HIV seropositive patients with CD4+ cell count over 200 cells/microL may be expected to benefit most from the test.
authors.affiliation: Clinical Epidemiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
authors.forename: Sirisak
authors.initials: S
authors.lastname: Nanta
authors.forename: Patcharee
authors.initials: P
authors.lastname: Kantipong
authors.forename: Panita
authors.initials: P
authors.lastname: Pathipvanich
authors.forename: Chidchanok
authors.initials: C
authors.lastname: Ruengorn
authors.forename: Chamaiporn
authors.initials: C
authors.lastname: Tawichasri
authors.forename: Jayanton
authors.initials: J
authors.lastname: Patumanond
mesh_terms: D017088:AIDS-Related Opportunistic Infections / Q000175:diagnosis; D000328:Adult; D000553:Ambulatory Care; D000907:Antibodies, Bacterial / Q000097:blood*; D002845:Chromatography / Q000379:methods; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D015658:HIV Infections / Q000175:diagnosis / Q000276:immunology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000379:methods; D013997:Time Factors; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000382:microbiology; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D011933:Reagent Kits, Diagnostic