Comparison of two interferon gamma release assays in the diagnosis of Mycobacterium tuberculosis infection and disease in The Gambia.
BMC Infect Dis
; 7: 122, 2007 Oct 25.
Article
em En
| MEDLINE
| ID: mdl-17961228
ABSTRACT
BACKGROUND:
IFN-gamma Release Assays (IGRAs) have been licensed for the diagnosis of latent Mycobacterium tuberculosis infection (LTBI). Their performance may depend on assay format and may vary across populations and settings. We compared the diagnostic performance of an in-house T -cell and commercial whole blood-based IGRAs for the diagnosis of LTBI and TB disease in The Gambia.METHODS:
Newly diagnosed sputum smear positive cases and their household contacts were recruited. Cases and contacts were bled for IGRA and contacts had a Mantoux skin test. We assessed agreement and discordance between the tests and categorized a contact's level of M. tuberculosis exposure according to where s/he slept relative to a case the same room, same house or a different house. We assessed the relationship between exposure and test results by multiple logistic regression.RESULTS:
In 80 newly diagnosed TB cases, the sensitivity of ELISPOT was 78.7% and for QFT-GIT was 64.0% (p = 0.047). Of 194 household contacts 57.1% and 58.8% were positive for ELISPOT and QFT-GIT respectively. The overall agreement between both IGRAs for LTBI in contacts was 71.4% and there was no significant discordance (p = 0.29). There was significant discordance between the IGRAs and TST. Neither IGRA nor TST had evidence of false positive results because of Bacille Calmette Guérin (BCG) vaccination. However, agreement between QFT-GIT and TST as well as discordance between both IGRAs and TST were associated with BCG vaccination. Both IGRAs responded to the M. tuberculosis exposure gradient and were positively associated with increasing TST induration (p = 0.003 for ELISPOT and p = 0.001 for QFT-GIT).CONCLUSION:
The ELISPOT test is more sensitive than the QFT-GIT for diagnosing TB disease. The two tests perform similarly in the diagnosis of LTBI in TB contacts. Significant discordance between the two IGRAs and between each and the TST remain largely unexplained.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tuberculose Pulmonar
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Ensaio de Imunoadsorção Enzimática
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Técnicas Bacteriológicas
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Interferon gama
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Mycobacterium tuberculosis
Tipo de estudo:
Diagnostic_studies
/
Etiology_studies
/
Incidence_studies
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Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Limite:
Adolescent
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Adult
/
Female
/
Humans
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Male
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Middle aged
País/Região como assunto:
Africa
Idioma:
En
Ano de publicação:
2007
Tipo de documento:
Article