Pulmonary tuberculosis: An analysis of isolation practices and clinical risk factors in a tertiary hospital

Background Inadequate isolation of patients with active pulmonary tuberculosis causes exposure whereas over-cautious isolation generates time and cost inefficiencies. This study aims to ascertain the delays involved in isolating subjects and the importance of risk factors. Methods and material Between December 2010 and January 2013, a retrospective analysis of 271 subjects was performed. Information was obtained from discharge letters, radiological and microbiological results. Results The median time taken to isolate subjects was 0 days, and 71.7% were isolated within 1 day. Most subjects (75.3%) had sputum samples obtained after isolation, of which 14.7% were positive. The median time from admission to first sputum sample was 1 day. Smear was negative in 174 subjects (85.3%). Country of birth (high or low risk) did not significantly affect sputum positivity (25.5% vs 19.4%, p=0.52). Suspicious radiological findings were noted in 38.6% subjects, and 32.8% had a suspicious clinical history. Subjects with both clinical and radiological probability had more sputum positivity (46.2%), compared to subjects who had neither (2.7%). Conclusion There are delays with isolation and diagnosis of subjects with a high probability of tuberculosis. Clinical and radiological probability were more significant in predicting sputum positivity than country of birth.