Recent advances in the laboratory diagnosis of tuberculosis.

The laboratory plays a decisive role in diagnosing tuberculosis (TB) and the identification and drug sensitivity testing (DST) of Mycobacterium tuberculosis. For a long time the laboratories used only microscopyand culture-based diagnosis, however, due to the slow growth of mycobacteria, these procedures may require 3-4 weeks or longer to yield results. It has been necessary to look for new and rapid diagnostic methods. In the beginning of the 90s, molecular-based diagnosis has become available providing rapid detection, identification and DST of M. tuberculosis. The present article will review some of the new methodology that has been introduced in the clinical laboratory. We discuss the LED microscope and PCRbased techniques for the diagnosis of TB, immunological assays for the diagnosis of active TB and latent infection, PCR-based methods and hybridization assays for the identification of mycobacteria and liquid culture methods and line probe assays for fast DST. Although these new techniques are useful for a rapid result, we emphasize that culture-based diagnosis is still the gold standard for the diagnosis and follow up on TB. The newer molecular methods cannot replace Corresponding authors: Dr. Rommy Teran Dr. Jacobus H. de Waard Faculty of Chemistry Central University of Ecuador E-mails: [email protected], [email protected]