Proof-of-concept evaluation of an automated sputum smear microscopy system for tuberculosis diagnosis

Show simple item record Lewis, James J. Chihota, Violet N. Van der Meulen, Minty Fourie, P.B. (Petrus Bernardus) Fielding, Katherine L. Grant, Alison D. Dorman, Susan E. Churchyard, Gavin J.
dc.contributor.editor Adithya, Cattamanchi 2013-01-31T13:13:57Z 2013-01-31T13:13:57Z 2012-11-29
dc.description.abstract BACKGROUND: ‘‘TBDx’’ is an innovative smear microscopy system that automatically loads slides onto a microscope, focuses and digitally captures images and then classifies smears as positive or negative using computerised algorithms. OBJECTIVES: To determine the diagnostic accuracy of TBDx, using culture as the gold standard, and compare this to a microscopist’s diagnostic performance. METHODS: This study is nested within a cross-sectional study of tuberculosis suspects from South African gold mines. All tuberculosis suspects had one sputum sample collected, which was decontaminated prior to smear microscopy, liquid culture and organism identification. All slides were auramine-stained and then read by both a research microscopist and by TBDx using fluorescence microscopes, classifying slides based on the WHO classification standard of 100 fields of view (FoV) at 4006 magnification. RESULTS: Of 981 specimens, 269 were culture positive for Mycobacterium tuberculosis (27.4%). TBDx had higher sensitivity than the microscopist (75.8% versus 52.8%, respectively), but markedly lower specificity (43.5% versus 98.6%, respectively). TBDx classified 520/981 smears (53.0%) as scanty positive. Hence, a proposed hybrid software/human approach that combined TBDx examination of all smears with microscopist re-examination of TBDx scanty smears was explored by replacing the ‘‘positive’’ result of slides with 1–9 AFB detected on TBDx with the microscopist’s original reading. Compared to using the microscopist’s original results for all 981 slides, this hybrid approach resulted in equivalent specificity, a slight reduction in sensitivity from 52.8% to 49.4% (difference of 3.3%; 95% confidence interval: 0.2%, 6.5%), and a reduction in the number of slides to be read by the microscopist by 47.0%. DISCUSSION: Compared to a research microscopist, the hybrid software/human approach had similar specificity and positive predictive value, but sensitivity requires further improvement. Automated microscopy has the potential to substantially reduce the number of slides read by microscopists. en_US
dc.description.librarian am2013 en_US
dc.description.librarian ay2013 en
dc.description.sponsorship The Consortium to Respond Effectively to the AIDS TB Epidemic, United States, who received funding from the Bill and Melinda Gates Foundation; the South African Mine Health and Safety Council; the Foundation for Innovative New Diagnostics, Switzerland; National Institutes of Health (NIH)/National Institutes of Allergy and Infectious Diseases award #AI077486; United Kingdom Department of Health (Public Health Career Scientist award to AG); NIH Fogarty ICORTA TB/AIDS (grants 5U2RTW007370 and 5U2RTW007373 to VC). en_US
dc.description.uri en_US
dc.identifier.citation Lewis JJ, Chihota VN, Van der Meulen M, Fourie PB, Fielding KL, et al. (2012) ‘‘Proof-Of-Concept’’ Evaluation of an Automated Sputum Smear Microscopy System for Tuberculosis Diagnosis. PLoS ONE 7(11): e50173. DOI: 10.1371/journal.pone.0050173 en_US
dc.identifier.issn 1932-6203
dc.identifier.other 10.1371/journal.pone.0050173
dc.language.iso en en_US
dc.publisher Public Library of Science en_US
dc.rights © 2012 Lewis et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, en_US
dc.subject Tuberculosis en_US
dc.subject Smear microscopy system en_US
dc.title Proof-of-concept evaluation of an automated sputum smear microscopy system for tuberculosis diagnosis en_US
dc.type Article en_US

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