A Comparison Of Three Versus Two Sputum Smear Microscopy In A Government Medical College, Patiala, India

Abstract

Introduction: Under the Revised National Tuberculosis Control Programme of India, three sputum samples are examined and 2 samples positivity criteria are used for labeling the patient as sputum positive pulmonary tuberculosis. Recent studies advocate use of two samples (one spot & one morning) for diagnosis of Tuberculosis. The objective was to compare three versus two sputum smears and to study the relevance of third sputum sample for microscopy in the current practice under Revised National Tuberculosis and Control Programme.

Methodology: A study of the laboratory register of the designated microscopic centre for the calendar year 2008 was undertaken. In all 9028 suspects were examined. An analysis of contribution of various sputum samples, S1 (fi rst spot sample), M (early morning) & S2 (second spot) towards diagnosis of Pulmonary Tuberculosis was undertaken.

Results: Sputum smear examination results of all the patients examined during 2008 were analyzed. Twelve hundred and eighty eight patients (99.3%) were labeled as smear positive tuberculosis when three sputum samples positivity criteria was considered. By applying two samples and any smear positivity criteria 1296 (99.9%) patients were labeled as sputum smear positive. Among 1296 smears, S1 was positive in 1088 (83.8%) and M in 1293 (99.6%) patients. Early morning sample positivity yield was found higher.

Conclusion: Considering 2 samples for examination with at least one morning specimen and one sample positivity criteria, the work load on laboratory can be reduced by 1/3rd without affecting case detection rate.

DOI: http://dx.doi.org/10.3126/saarctb.v8i2.5898

SAARCTB 2011; 8(2): 28-30