Contemporary approaches to the serology of tuberculosis

The current approaches in serological methods for the diagnosis of tuberculosis have been towards the use of M. tuberculosis-specific antigens or epitopes of protein antigens. Although sensitivity by using such antigens might be similar to that obtained by using crude or semipurified antigens, specificity was somewhat improved to over 95%. Among serological tools, ELISA has been the method of choice for detecting serum antibodies and mycobacterial antigens from clinical specimens because of its high sensitivity, simplicity, reproducibility and versatility in screening a large number of specimens. Further simple and rapid tests such as the agglutination test by coating various particles with purified or synthetic M. tuberculosis-specific antigens or antibodies will soon become available for field evaluation in endemic areas of tuberculosis. However, all these efforts can be justified only if serological tests give any meaningful information for the diagnosis and management of tuberculosis or for determining the degree of M. tuberculosis transmission in a community as a complement to the current tuberculin test, chest X-ray, or sputum examination. Although the detection of mycobacterial antigens from CSF or sputum specimens using polyclonal or monoclonal antibodies gave more direct evidence for M. tuberculosis infection, the information by the assays was not sufficient to determine whether these immunological tools could be used in clinical laboratories for the diagnosis of tuberculosis. Meanwhile, recent introduction of the very sensitive polymerase chain reaction (PCR) technology for the detection of M. tuberculosis DNA from clinical specimens (37-40) may eventually replace the immunological assays for the detection of mycobacterial antigens.(ABSTRACT TRUNCATED AT 250 WORDS)