title: Accuracy and utility of commercially available amplification and serologic tests for the diagnosis of minimal pulmonary tuberculosis.
abstract: Diagnosis of patients with minimal active tuberculosis (TB) is difficult, as there is no single test with high sensitivity and specificity. The yield and clinical utility of a combination of diagnostic tests were prospectively studied among 500 consecutive patients referred for sputum induction for diagnosis of possible active TB. Patients underwent sputum induction, chest X-ray, tuberculin testing, and had blood drawn for serologic testing (Detect-TB test; Biochem ImmunoSystems). Sputum was examined with fluorescent microscopy and PCR (Amplicor MTB-Roche) and cultured for mycobacteria using liquid (BACTEC) and solid media. For the diagnosis of the 60 cases of active TB, sensitivity and specificity, respectively, of the following diagnostic tests were mycobacterial culture, 73% and 100%; PCR, 42% and 100%; chest X-ray, 67-77% and 66-76%; tuberculin testing, 94% and 20%; and serology, 33% and 87%. After consideration of PCR and radiographic and clinical characteristics, a positive serologic test was independantly associated with diagnosis of active disease (adjusted odds of disease if positive, 2.6; 95% confidence limits, 1.1,6.1). No currently available test has sensitivity and specificity high enough for the accurate diagnosis of minimal pulmonary TB. Utilization of a combination of tests, together with consideration of key clinical characteristics, could improve diagnostic accuracy.
authors.affiliation: Montreal Chest Institute, Respiratory Epidemiology Unit, Department of Microbiology of the Royal Victoria Hospital, McGill University; Hopital Maisonneuve Rosemont, University of Montreal, Montreal, Quebec, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Al Zahrani
authors.forename: H
authors.initials: H
authors.lastname: Al Jahdali
authors.forename: L
authors.initials: L
authors.lastname: Poirier
authors.forename: P
authors.initials: P
authors.lastname: René
authors.forename: M L
authors.initials: ML
authors.lastname: Gennaro
authors.forename: D
authors.initials: D
authors.lastname: Menzies
mesh_terms: D000328:Adult; D000368:Aged; D000907:Antibodies, Bacterial / Q000097:blood*; D001431:Bacteriological Techniques; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D014374:Tuberculin Test; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial