Diagnostic defaulters: an overlooked aspect in the Indian Revised National Tuberculosis Control Program

The Revised National Tuberculosis Control Program (RNTCP) aims to achieve detection of 70% of new smear-positive patients in a community and to cure 85% of such patients. Though an elaborate recording and reporting system is in place to monitor the success of the program, no record of patients who do not complete the diagnostic process is currently maintained. The present study, performed in a tertiary care hospital, attempted to estimate the proportion of this group of patients, who were labeled "diagnostic defaulters.

This prospective observational study was conducted over one year on consecutive patients presenting with cough of more than two weeks' duration. A total of two sputum samples were obtained from each patient, including a spot sample and a morning sample collected on the following day. Zeihl-Neelsen staining, reporting and external quality assessment of smear-microscopy was done per RNTCP guidelines.

Of the 2,349 patients recruited, 175 defaulted on the second day. The positivity rates for the spot and morning samples were 18.3% and 18.9%, respectively (p > 0.001).  Of the 175 defaulters, 31 were found to be smear-positive, thereby implying that the proportion of diagnostic defaulters was 17.7%. All 21 diagnostic defaulters contacted by telephone were found to be unaware of their smear-positive status.

The high proportion of diagnostic defaulters, the majority of whom were unaware of their sputum-positive status, emphasizes the need to recognize the importance of this group of patients to better control tuberculosis.