Value of ELISA IgG and IgM Antibodies using A60 Antigen in the Diagnosis of Tuberculosis

Objectives: To evaluate a new Modified Anda-TB IgG ELISA test for the serodiagnosis of Mycobacterium tuberculosis in patients and controls. Settings and duration: The study was carried out between January to December 2010 at the Microbiology Department, Umm Al-Qura University, Makkah. Patients and Methods: The Anda IgG and IgM ELISA tests were run on 674 patient’s sera which included 378 active cases of TB, 196 patients suffering from lower respiratory tract infections and 100 healthy blood donors. The ages of the patients (active cases of pulmonary tuberculosis and lower respiratory tract infections) and controls, ranged from 15-85 years with a mean age of 37 years. Smear and culture examinations were done according to standard procedures. Sera were obtained from the patients before receiving anti-tuberculosis chemotherapy and were stored at -70°C until they were tested. Patients were excluded from the study if they had received anti-tuberculosis drugs within the preceding 12 months. Results: Anda IgG antibodies were found in 230/378 (61%) patients with active pulmonary tuberculosis, in lower respiratory tract infection (LRT) group, 24/196 (12.2%) patients were positive, while 6% were positive in the healthy blood donor group. Anda IgM was positive in 29/378 (7.7%) patients with active TB, 5.6% with LRT and 1% blood donors. Conclusion: This study showed that about 61 % active TB patients had Anda IgG antibodies against A 60 antigen while, only 8% had Anda IgM.