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The value of xpert MTB/RIF-generated CT values for predicting the smear status of patients with pulmonary tuberculosis

BACKGROUND: Smear microscopy is used to assess the patient's infectiousness at the time of initial diagnosis of pulmonary tuberculosis. However, its limited sensitivity and specificity highlights the need for new diagnostic strategies. The aim of our study was to assess the diagnostic accuracy...

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Autores principales: Fradejas, Isabel, Ontañón, Belén, Muñoz-Gallego, Irene, Ramírez-Vela, M.J., López-Roa, Paula
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Elsevier 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6830157/
https://www.ncbi.nlm.nih.gov/pubmed/31720405
http://dx.doi.org/10.1016/j.jctube.2018.04.002
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author Fradejas, Isabel
Ontañón, Belén
Muñoz-Gallego, Irene
Ramírez-Vela, M.J.
López-Roa, Paula
author_facet Fradejas, Isabel
Ontañón, Belén
Muñoz-Gallego, Irene
Ramírez-Vela, M.J.
López-Roa, Paula
author_sort Fradejas, Isabel
collection PubMed
description BACKGROUND: Smear microscopy is used to assess the patient's infectiousness at the time of initial diagnosis of pulmonary tuberculosis. However, its limited sensitivity and specificity highlights the need for new diagnostic strategies. The aim of our study was to assess the diagnostic accuracy of GX Ct value as a predictor of smear status and its usefulness to quantify mycobacterial load. METHODS: All GX-positive sputum samples during a seven-year period were included in the study. Correlations among Ct values, smear status and TTD on liquid culture were calculated. An optimal Ct value for ruling in infectious patients was established. Clinical and radiological variables were also analyzed. RESULTS: Sixty-eight samples from 65 patients were included. Ct value and TTD yielded a positive correlation (ρ = 0.714; p < 0.05), while Ct and smear grade yielded an inverse correlation (r = −0.71). An optimal Ct value for ruling in smear positive patients was established at 21.1 cycles (90.5% sensitivity, 61% specificity, 81% PPV and 78% NPV). CONCLUSIONS: Our study confirms the value of GX Ct levels for quantifying mycobacterial load and demonstrates the added value of Ct as a predictor of positive smear status, especially at Ct values below 21.
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spelling pubmed-68301572019-11-12 The value of xpert MTB/RIF-generated CT values for predicting the smear status of patients with pulmonary tuberculosis Fradejas, Isabel Ontañón, Belén Muñoz-Gallego, Irene Ramírez-Vela, M.J. López-Roa, Paula J Clin Tuberc Other Mycobact Dis Article BACKGROUND: Smear microscopy is used to assess the patient's infectiousness at the time of initial diagnosis of pulmonary tuberculosis. However, its limited sensitivity and specificity highlights the need for new diagnostic strategies. The aim of our study was to assess the diagnostic accuracy of GX Ct value as a predictor of smear status and its usefulness to quantify mycobacterial load. METHODS: All GX-positive sputum samples during a seven-year period were included in the study. Correlations among Ct values, smear status and TTD on liquid culture were calculated. An optimal Ct value for ruling in infectious patients was established. Clinical and radiological variables were also analyzed. RESULTS: Sixty-eight samples from 65 patients were included. Ct value and TTD yielded a positive correlation (ρ = 0.714; p < 0.05), while Ct and smear grade yielded an inverse correlation (r = −0.71). An optimal Ct value for ruling in smear positive patients was established at 21.1 cycles (90.5% sensitivity, 61% specificity, 81% PPV and 78% NPV). CONCLUSIONS: Our study confirms the value of GX Ct levels for quantifying mycobacterial load and demonstrates the added value of Ct as a predictor of positive smear status, especially at Ct values below 21. Elsevier 2018-04-14 /pmc/articles/PMC6830157/ /pubmed/31720405 http://dx.doi.org/10.1016/j.jctube.2018.04.002 Text en © 2018 Published by Elsevier Ltd. http://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
spellingShingle Article
Fradejas, Isabel
Ontañón, Belén
Muñoz-Gallego, Irene
Ramírez-Vela, M.J.
López-Roa, Paula
The value of xpert MTB/RIF-generated CT values for predicting the smear status of patients with pulmonary tuberculosis
title The value of xpert MTB/RIF-generated CT values for predicting the smear status of patients with pulmonary tuberculosis
title_full The value of xpert MTB/RIF-generated CT values for predicting the smear status of patients with pulmonary tuberculosis
title_fullStr The value of xpert MTB/RIF-generated CT values for predicting the smear status of patients with pulmonary tuberculosis
title_full_unstemmed The value of xpert MTB/RIF-generated CT values for predicting the smear status of patients with pulmonary tuberculosis
title_short The value of xpert MTB/RIF-generated CT values for predicting the smear status of patients with pulmonary tuberculosis
title_sort value of xpert mtb/rif-generated ct values for predicting the smear status of patients with pulmonary tuberculosis
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6830157/
https://www.ncbi.nlm.nih.gov/pubmed/31720405
http://dx.doi.org/10.1016/j.jctube.2018.04.002
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