Evaluation of bacteriological diagnosis of smear positive pulmonary tuberculosis under programme conditions in three districts in the context of dots implementation in India.

ABSTRACT

Objective: To study the smear and culture positivity rates in pulmonary tuberculosis patients declared as smear positive in the districts of North Arcot (Tamil Nadu), Raichur (Karnataka) and Wardha (Maharashtra) in India in order to evaluate the diagnosis of pulmonary tuberculosis at the field level under programme conditions. Methods: Two specimens of sputum from each of 320 patients in North Arcot, 314 patients in Raichur and 302 patients from Wardha district, all of whom had been reported as smear-positive at the field level, were examined by smear and culture. Findings: The proportion of specimens found to be smear-negative was 4.7% in North Arcot and 5.7% in Raichur as against 38.7% in Wardha. The proportions of culture negative specimens were 5.7% and 6.3% respectively in North Arcot and Raichur, while it was 35.6% at Wardha. The difference in the smear and culture negativity between Wardha and the other two districts was highly significant. Conclusions: The study revealed an unacceptably high level of false positives in sputum smear microscopy in the Wardha district. This could be attributed to the absence of systematic and intensive training in smear examination consequent to the non-implementation of the DOTS strategy in this district and a high standard of training offered in the RNTCP implemented districts.