title: Specimen dilution improves sensitivity of the amplified Mycobacterium tuberculosis direct test for smear microscopy-positive respiratory specimens.
abstract: Specimen dilution has been proposed as a strategy to minimize amplified Mycobacterium tuberculosis direct (MTD) test inhibition (N. Pollock, J. Westerling, and A. Sloutsky, Am. J. Clin. Pathol. 126:142-147, 2006; A. Sloutsky, L. L. Han, and B. G. Werner, J. Clin. Microbiol. 42:1547-1551, 2004). We evaluated the impact of respiratory specimen dilution on MTD test accuracy in a public health laboratory. The difference in MTD test sensitivity between the dilution and conventional methods was 15.9% (P = 0.001) for smear microscopy-positive specimens and -3.6% (P = 0.38) for smear microscopy-negative specimens.
authors.affiliation: Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Renata L
authors.initials: RL
authors.lastname: Guerra
authors.forename: James F
authors.initials: JF
authors.lastname: Baker
authors.forename: Roya
authors.initials: R
authors.lastname: Alborz
authors.forename: Derek T
authors.initials: DT
authors.lastname: Armstrong
authors.forename: Julia A
authors.initials: JA
authors.lastname: Kiehlbauch
authors.forename: Marcus B
authors.initials: MB
authors.lastname: Conde
authors.forename: Susan E
authors.initials: SE
authors.lastname: Dorman
authors.forename: Nancy M
authors.initials: NM
authors.lastname: Hooper
mesh_terms: D001826:Body Fluids / Q000382:microbiology; D006801:Humans; D008853:Microscopy; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000302:isolation & purification*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000175:diagnosis*