Defining an intermediate category of tuberculin skin test: A mixture model analysis of two high-risk populations from Kampala, Uganda.

One principle of tuberculosis control is to prevent the development of tuberculosis disease by treating individuals with latent tuberculosis infection. The diagnosis of latent infection using the tuberculin skin test is not straightforward because of concerns about immunologic cross reactivity with...

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Main Authors: Henok G Woldu, Sarah Zalwango, Leonardo Martinez, María Eugenia Castellanos, Robert Kakaire, Juliet N Sekandi, Noah Kiwanuka, Christopher C Whalen
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2021-01-01
Series:PLoS ONE
Online Access:https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0245328&type=printable
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author Henok G Woldu
Sarah Zalwango
Leonardo Martinez
María Eugenia Castellanos
Robert Kakaire
Juliet N Sekandi
Noah Kiwanuka
Christopher C Whalen
author_facet Henok G Woldu
Sarah Zalwango
Leonardo Martinez
María Eugenia Castellanos
Robert Kakaire
Juliet N Sekandi
Noah Kiwanuka
Christopher C Whalen
author_sort Henok G Woldu
collection DOAJ
description One principle of tuberculosis control is to prevent the development of tuberculosis disease by treating individuals with latent tuberculosis infection. The diagnosis of latent infection using the tuberculin skin test is not straightforward because of concerns about immunologic cross reactivity with the Bacille Calmette-Guerin (BCG) vaccine and environmental mycobacteria. To parse the effects of BCG vaccine and environmental mycobacteria on the tuberculin skin test, we estimated the frequency distribution of skin test results in two divisions of Kampala, Uganda, ten years apart. We then used mixture models to estimate parameters for underlying distributions and defined clinically meaningful criteria for latent infection, including an indeterminate category. Using percentiles of two underlying normal distributions, we defined two skin test readings to demarcate three ranges. Values of 10 mm or greater contained 90% of individuals with latent infection; values less than 7.2 mm contained 80% of individuals without infection. Contacts with values between 7.2 and 10 mm fell into an indeterminate zone where it was not possible to assign infection. We conclude that systematic tuberculin skin test surveys within populations at risk, combined with mixture model analysis, may be a reproducible, evidence-based approach to define meaningful criteria for latent tuberculosis infection.
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institution Kabale University
issn 1932-6203
language English
publishDate 2021-01-01
publisher Public Library of Science (PLoS)
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spelling doaj-art-52c4e5fb12cf46c1b803b5ef9a1c13392025-08-20T03:44:47ZengPublic Library of Science (PLoS)PLoS ONE1932-62032021-01-01161e024532810.1371/journal.pone.0245328Defining an intermediate category of tuberculin skin test: A mixture model analysis of two high-risk populations from Kampala, Uganda.Henok G WolduSarah ZalwangoLeonardo MartinezMaría Eugenia CastellanosRobert KakaireJuliet N SekandiNoah KiwanukaChristopher C WhalenOne principle of tuberculosis control is to prevent the development of tuberculosis disease by treating individuals with latent tuberculosis infection. The diagnosis of latent infection using the tuberculin skin test is not straightforward because of concerns about immunologic cross reactivity with the Bacille Calmette-Guerin (BCG) vaccine and environmental mycobacteria. To parse the effects of BCG vaccine and environmental mycobacteria on the tuberculin skin test, we estimated the frequency distribution of skin test results in two divisions of Kampala, Uganda, ten years apart. We then used mixture models to estimate parameters for underlying distributions and defined clinically meaningful criteria for latent infection, including an indeterminate category. Using percentiles of two underlying normal distributions, we defined two skin test readings to demarcate three ranges. Values of 10 mm or greater contained 90% of individuals with latent infection; values less than 7.2 mm contained 80% of individuals without infection. Contacts with values between 7.2 and 10 mm fell into an indeterminate zone where it was not possible to assign infection. We conclude that systematic tuberculin skin test surveys within populations at risk, combined with mixture model analysis, may be a reproducible, evidence-based approach to define meaningful criteria for latent tuberculosis infection.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0245328&type=printable
spellingShingle Henok G Woldu
Sarah Zalwango
Leonardo Martinez
María Eugenia Castellanos
Robert Kakaire
Juliet N Sekandi
Noah Kiwanuka
Christopher C Whalen
Defining an intermediate category of tuberculin skin test: A mixture model analysis of two high-risk populations from Kampala, Uganda.
PLoS ONE
title Defining an intermediate category of tuberculin skin test: A mixture model analysis of two high-risk populations from Kampala, Uganda.
title_full Defining an intermediate category of tuberculin skin test: A mixture model analysis of two high-risk populations from Kampala, Uganda.
title_fullStr Defining an intermediate category of tuberculin skin test: A mixture model analysis of two high-risk populations from Kampala, Uganda.
title_full_unstemmed Defining an intermediate category of tuberculin skin test: A mixture model analysis of two high-risk populations from Kampala, Uganda.
title_short Defining an intermediate category of tuberculin skin test: A mixture model analysis of two high-risk populations from Kampala, Uganda.
title_sort defining an intermediate category of tuberculin skin test a mixture model analysis of two high risk populations from kampala uganda
url https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0245328&type=printable
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