Age and Sex Differences in Sputum Smear Microscopy Results for Acid Fast Bacilli in a Tertiary Care Centre, South India

摘要

Background and Objectives. Low counts are more difficult to find in microscopic sputum examination and thus are more likely to be missed. In this study, we aimed to estimate the proportion of low-count grading and assessing any age and gender differences in sputum smear grading in a low HIV prevalence setting.Materials and Methods. From the tuberculosis laboratory register information on sputum positivity including the grading of smears, age and gender were extracted for January 2011–December 2011. Smears were examined using Ziehl-Neelsen technique and graded as per the Program Guidelines. Positive smears were classified into low grade positive smears (scanty and 1+) and high grade positive smears (2+ and 3+). Differences in grading of smear based on gender and age were analysed using chi square test.Results. Of 9000 smears examined, 8210 (91.2%) were collected as diagnostic smears from tuberculosis suspects. Low grade positivity was 37.5% among diagnostic smears and 69.6% among follow-up smears. Sputum smears from female examinees had higher proportions of low grade positive smears(P=0.003). Stratification of age and sex within TB suspects had clearly demonstrated the observance of higher low grade positivity among female TB suspects at extremes of age.