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Performance of a molecular assay to detect Mycobacterium tuberculosis  complex DNA in clinical specimens: multicenter study in Brazil
Verza, Mirela; Schmid, Karen Barros; Barcellos, Regina Bones; Linck, Natali; Bello, Graziele Lima; Scapin, Daniel; Sperhacke, Rosa Dea; Silva, Márcia Susana Nunes; Wollheim, Claudia; Rivero, Martha Gabriela Celle; Kritski, Afrânio Lineu; Rezende Jr, Leonides; Oliveira, Martha Maria; Costa, Elis Regina Dalla & Rossetti, Maria Lucia Rosa
Abstract
BACKGROUND In high tuberculosis (TB) burden countries, there are few data on the performance of new molecular commercialised
assays developed locally.
OBJECTIVE To evaluate the performance of a new molecular commercialised assay for TB diagnosis (Detect-TB) in three laboratories.
METHODS A total of 302 sputum samples from an equal number of patients with presumptive diagnosis of pulmonary tuberculosis
(PTB) were submitted for routine smear microscopy, culture, and Detect-TB assay at three different sites in Brazil (the cities of
Caxias do Sul, São Paulo and Canoas).
FINDINGS Seventy four (24.7%) TB cases were diagnosed (65 bacteriologically confirmed). When compared to smear microscopy/culture results, the overall sensitivity and specificity of Detect-TB assay was 84.6% (CI 95%; 73.7-91.6) and 93.1% (CI 95%; 89.1-95.8), respectively. When compared to bacteriological and clinical diagnostic criteria, the sensitivity and specificity of Detect-TB
assay was 74.3% (CI 95%; 63.3-82.9) and 92.9% (CI 95%; 88.7-95.6), respectively. Among the three sites - Caxias do Sul, São
Paulo and Canoas - the sensitivity and specificity were respectively 94.7% and 97.8%; 71.4% and 93.9%, 82.1% and 88.9%.
MAIN CONCLUSIONS These findings suggest that the Detect-TB assay could be applied routinely in reference laboratories across
different regions in Brazil.
Keywords
tuberculosis; reverse-hybridisation assay; IS6110; molecular diagnosis; Detect-TB
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