New methods for the diagnosis of tuberculosis

Abstract

The magnitude of the global tuberculosis problem and its potential for increase have led to efforts to improve the diagnostic methods as one of the leading control strategies. New diagnostic tools have been developed, including direct detection tests, rapid culture media and identification methods. For the direct detection of mycobacteria, tests based on nucleic acid amplification have been implemented, with higher sensitivity than the direct smear, close to that of the cultures; however, they are still expensive methods. Availability of the automated cultures resulted in a radical change in mycobacteriology, reducing the time required for the isolation of Mycobacterium tuberculosis. The combination of rapid methods has increased the rates of isolation and decreased the time required for the detection of growth. Different tools for identifying mycobacteria have also been developed, aimed at improving the performance of traditional biochemical methods and achieving species identification in a few hours. The new diagnostic alternatives have succeeded in improving the sensitivity, specificity and speed in the diagnosis of tuberculosis; however, the challenge remains to reduce their cost and to make them more accessible in countries where the problem with this disease is still serious.