Mycobacterium tuberculosis complex is not detected by DNA amplification assay in sputum specimens of patients with lung scars due to past pulmonary tuberculosis.
OBJECTIVE: To evaluate detection of false-positive sputum amplification assay results in former tuberculosis patients with residual pulmonary scars. DESIGN: A total of 268 sputum specimens from 25 war veterans with tuberculosis during 1940-1959, without adequate chemotherapy, and 19 subjects effectively treated for cavitary tuberculosis during 1980-1993 were tested by smear, culture and DNA amplification, as were 34 controls with no history of tuberculosis or pulmonary scars. RESULTS: No active tuberculosis cases were identified. All specimens were negative on DNA amplification and smear. Eight specimens from six subjects were positive on culture, revealing atypical mycobacteria. CONCLUSION: No genetic Mycobacterium tuberculosis material in sputum specimens of subjects with residual lesions of pulmonary tuberculosis and no false-positive amplification results were detected.