Impact of Sputum Volume in the Diagnosis of Smear-Positive Pulmonary Tuberculosis

OBJECTIVE: To find the impact of sputum volume in the diagnosis of smear-positive (SP) pulmonary tuberculosis (PT) and its association with gender. MATERIALS AND METHODS: The study was conducted in the Department of Microbiology, GSL Medical College. PT patients were included and informed to provide good-quality sputum; volume was not mentioned. Smears were stained by Ziehl–Neelsen technique. Based on the volume of sample submitted, the participants were divided into three groups. Chi-square test was used to find the statistical significance; P < 0.05 was considered statistically significant. RESULTS: Volume-wise, 22, 38, and 74 participants submitted sputum, respectively, in groups, <2 mL, 2–5 mL, and >5 mL; statistically, the difference was significant (P < 0.05). The smear positivity was 13% (15), 28% (32), and 59% (68), respectively, in groups, <2 mL, 2–5 mL, and >5 mL; statistically, the difference was significant (P < 0.05). Among the missed cases, the difference was statistically significant (P < 0.05) in males and the difference was statistically not significant (P > 0.05) in females. CONCLUSIONS: Notable number of SP cases are identified in ≤5 mL sputum. Hence, sample should not be discarded/rejected if the volume is <5 mL.