ABSTRACT
OBJECTIVE: To compare the accuracy of the amplified Mycobacterium tuberculosis direct (AMTD) test with reference methods for the laboratory diagnosis of tuberculosis in HIV-infected patients. METHODS: This was a study of diagnostic accuracy comparing AMTD test results with those obtained by culture on Löwenstein-Jensen (LJ) medium and by the BACTEC Mycobacteria Growth Indicator Tube 960 (BACTEC MGIT 960) system in respiratory samples analyzed at the Bioassay and Bacteriology Laboratory of the Oswaldo Cruz Foundation Evandro Chagas Clinical Research Institute in the city of Rio de Janeiro, Brazil. RESULTS: We analyzed respiratory samples collected from 118 patients, of whom 88 (74.4%) were male. The mean age was 36.6 ± 10.6 years. Using the AMTD test, the BACTEC MGIT 960 system, and LJ culture, we identified M. tuberculosis complex in 31.0%, 29.7%, and 27.1% of the samples, respectively. In comparison with LJ culture, the AMTD test had a sensitivity, specificity, positive predictive value, and negative predictive value of 87.5%, 89.4%, 75.7%, and 95.0%, respectively, for LJ culture, whereas, in comparison with the BACTEC MGIT 960 system, it showed values of 88.6%, 92.4%, 83.8%, and 94.8%, respectively. CONCLUSIONS: The AMTD test showed good sensitivity and specificity in the population studied, enabling the laboratory detection of M. tuberculosis complex in paucibacillary respiratory specimens.
Subject(s)
Culture Media , HIV Infections/complications , Mycobacterium tuberculosis/isolation & purification , Sputum/microbiology , Tuberculosis, Pulmonary/complications , Tuberculosis, Pulmonary/diagnosis , Bacteriological Techniques/methods , Brazil , Female , Humans , Male , Predictive Value of Tests , Sensitivity and SpecificityABSTRACT
OBJECTIVE: To compare the accuracy of the amplified Mycobacterium tuberculosis direct (AMTD) test with reference methods for the laboratory diagnosis of tuberculosis in HIV-infected patients. METHODS: This was a study of diagnostic accuracy comparing AMTD test results with those obtained by culture on Löwenstein-Jensen (LJ) medium and by the BACTEC Mycobacteria Growth Indicator Tube 960 (BACTEC MGIT 960) system in respiratory samples analyzed at the Bioassay and Bacteriology Laboratory of the Oswaldo Cruz Foundation Evandro Chagas Clinical Research Institute in the city of Rio de Janeiro, Brazil. RESULTS: We analyzed respiratory samples collected from 118 patients, of whom 88 (74.4%) were male. The mean age was 36.6 ± 10.6 years. Using the AMTD test, the BACTEC MGIT 960 system, and LJ culture, we identified M. tuberculosis complex in 31.0%, 29.7%, and 27.1% of the samples, respectively. In comparison with LJ culture, the AMTD test had a sensitivity, specificity, positive predictive value, and negative predictive value of 87.5%, 89.4%, 75.7%, and 95.0%, respectively, for LJ culture, whereas, in comparison with the BACTEC MGIT 960 system, it showed values of 88.6%, 92.4%, 83.8%, and 94.8%, respectively. CONCLUSIONS: The AMTD test showed good sensitivity and specificity in the population studied, enabling the laboratory detection of M. tuberculosis complex in paucibacillary respiratory specimens. .
OBJETIVO: Comparar a acurácia do teste amplified Mycobacterium tuberculosis direct (AMTD) com métodos de referência para o diagnóstico laboratorial de tuberculose em pacientes HIV positivos. MÉTODOS: Estudo de acurácia diagnóstica comparando os resultados do teste AMTD com os de cultura em Löwenstein-Jensen (LJ) e de BACTEC Mycobacteria Growth Indicator Tube 960 (sistema BACTEC MGIT 960) em amostras respiratórias analisadas no Laboratório de Bacteriologia e Bioensaios do Instituto de Pesquisa Clínica Evandro Chagas da Fundação Oswaldo Cruz, no Rio de Janeiro (RJ). RESULTADOS: Foram analisadas amostras respiratórias de 118 pacientes, dos quais 88 (74,4%) eram do sexo masculino. A média de idade foi de 36,6 ± 10,6 anos. O complexo M. tuberculosis foi identificado em 31,0%, 29,7% e 27,1% das amostras através do teste AMTD, sistema BACTEC MGIT 960 e LJ, respectivamente. Na comparação com a cultura em LJ, o teste AMTD apresentou sensibilidade, especificidade, valor preditivo positivo e valor preditivo negativo de 87,5%, 89,4%, 75,7% e 95,0%, respectivamente, enquanto na comparação com o sistema BACTEC MGIT 960, os valores foram de 88,6%, 92,4%, 83,8% e 94,8%, respectivamente. CONCLUSÕES: O teste AMTD mostrou boa sensibilidade e especificidade na população estudada, possibilitando a detecção laboratorial do complexo M. tuberculosis em espécimes respiratórios paucibacilares. .