An alternative 1‐day smear microscopy protocol for the diagnosis of pulmonary tuberculosis

Background and objective: This study was undertaken to assess the feasibility of diagnosing pulmonary tuberculosis (PTB) by collecting two sputum samples on a single day (1‐day protocol), and to compare this protocol with the national policy of collecting two samples on consecutive days (2‐day protocol). Methods: A total of 513 individuals with cough that had persisted for more than 2 weeks were screened for PTB by collection of three sputum samples: a spot sample on the first day, a sample collected 1 h after the first sample and a sample collected the following morning. For the 2‐day protocol, the diagnostic performance of the first and third samples was considered, while the 1‐day protocol was evaluated using the two samples collected on the first day. Staining and microscopy were performed in a blinded manner by two different technicians. Results: Of the 513 patients, 40 defaulted on the second day. Of the total number of patients recruited, 124 (24.2%) were smear‐positive. Using the 2‐day protocol, 121 patients (97.6%) were identified as smear‐positive, whereas with the 1‐day protocol 118 patients (95.2%) were identified as smear‐positive (P = 0.3). Of the patients who defaulted, seven (17.5%) were smear‐positive. Comparison of the variation in results indicated that collection of a morning sample on the second day provided no significant benefit over collection of a second spot sample on the first day. Conclusions: As the 2‐day protocol did not show a statistically significant difference in diagnostic performance compared with the 1‐day protocol, the latter may be adopted as an alternative protocol, particularly for patients who are more likely to default.