Comparison of Culture, Real-Time DNA Amplification Assay and Ehrlich-Ziehl-Neelsen for Detection of Mycobacterium tuberculosis.

Abstract

Mycobacterium tuberculosis is still a substantial health problem universally. Although culture is the gold standard method, reliable, rapid and new methods are required for effective struggle with disease. We retrospectively compared the results of Ehrlich-Ziehl-Neelsen (EZN) stain and real-time DNA amplification assay (BD ProbeTec ET system) with culture. Retrospective study. A total of 703 samples, 182 pulmonary and 521 extra pulmonary, collected from 630 patients between May 2008 and February 2011 were evaluated. Culture was considered the gold standard. For pulmonary specimens, sensitivity, specificity, positive predictive and negative predictive values of BD ProbeTec ET and EZN were calculated to be 100%, 98.8%, 87.5%, 100% and 71.4%, 98.8%, 83.3%, 97.6%, respectively. For extra pulmonary specimens, sensitivity, specificity, positive predictive and negative predictive values of BD ProbeTec ET and EZN were calculated to be 80%, 98.7%, 76.9%, 98.9% and 24%, 98.3%, 42.8%, 96.2%, respectively. According to these results, we suggest that the BD ProbeTec ET system is more reliable than EZN. In addition, the BD ProbeTec ET system produces faster results. Based upon these results, we consider that the BD ProbeTec ET system may be employed in the diagnosis of M. tuberculosis.