Diagnosis of mycobacterial disease by biochemical and immunological parameters

A definitive diagnosis of tuberculosis requires the recovery of M. tuberculosis organisms from a patient's secretions, body fluids, or tissues. However, the detection rate of M. tuberculosis is not high in tuberculous pleural effusions. Several studies demonstrated that adenosine deaminase (ADA) level in pleural effusion above 50 IU/L was strongly associated with tuberculosis. ADA has been found to be elevated in serum and several body fluids that are infected by M. tuberculosis. Recently, the simultaneous skin tests of PPDs (M. tuberculosis), PPD-B (M. intracellulare), PPD-Y (M. kansasii) and PPD-F (M. fortuitum), have been reported to be useful in diagnosing mycobacteriosis in the early stage of the disease. Although serodiagnosis of tuberculosis has long been the subject of investigation, no serodiagnostic approach is currently of widespread and clinical utility. At the present time, several serodiagnostic test using enzyme-linked immunosorbent assay (ELISA) for the measurement of IgG antibody to some protein (38-kDa, 30-kDa, 16-kDa and so on) and nonprotein (lipoarabinomannan and cord factor) antigens. Despite an explosion in the techniques of rapid identification of mycobacteria by molecular genetic means, the relative simplicity and low cost of serodiagnosis remain attractive.