Serodiagnosis of extrapulmonary mycobacteriosis by ELISA using 30,000 Da and PPD antigens

ABSTRACT

Serological diagnosis of 31 cases of extrapulmonary Mycobacteriosis [21 meningitis, 8 urinary, 10 bone and joint and one endometritis cases] 8 controls of other extrapulmonary cases and 16 healthy controls. ELISA test was used to detect serum Ig[G] and Ig[M] antibodies to 30, 000 Dalton [Da] and purified protein derivative [PPD] antigens of M. tuberculosis. The results were statistically analysed by accuracy index, sensitivity, specificity, positive and negative predictive values. Ig[G] detection using 30, 000 Da gave a higher sensitivity than PPD [66.6% and 52% respectively], while both antigens gave 100% specificity. On the other hand, the dual antigen gave a sensitivity of 85.7% and specificity 100%. A higher statistical significant difference was observed between cases and controls [P<0.005]. Detection of specific Ig[M] antibodies revealed no appreciable diagnostic value. It can be concluded from this study that the use of the dual antigen for detection of Ig[G] was reliable for the diagnosis of mycobacterial infection, however, it can't differentiate between Mycobacterial tuberculosis and other mycobacteria