INTRODUCTION: A large number of tuberculosis cases are continuously being reported from India and other developing countries leading to high morbidity and mortality. In spite of many newer tests available for diagnosing a case of tuberculosis, smear microscopy of sputum is still the preferred test under programmatic conditions. The current national and international guidelines recommend two sputum smear examinations in two days for diagnosing cases of tuberculosis, which is time-consuming, tedious, needs multiple visits, leading to high dropout of infectious cases. In the background of existing limitations of smear microscopy, we attempted to complete the diagnosis of tuberculosis on same day by serial collection of the spot sputum specimen and analyze its advantages, feasibility and viability. MATERIAL & METHODS: The study was undertaken by the Department of Microbiology, Lala Ram Sarup Institute of Tuberculosis and Respiratory Diseases during May 2010 to April 2011. Sputum specimens were collected from 330 randomly selected tuberculosis suspects who attended OPD of hospital, patients submitted spot and home collected morning sputum sample in a standard method and spot and additional spot sputum (X- spot) collected one hour after the first spot sample as per the proposed front loading method. All the samples received were stained by acid fast Ziehl-Neelsen (ZN) stain and examined on the same day. The sputum sample was pooled and cultured in Lowenstein Jensen (LJ) media in duplicate set of bottles. The results of two different microscopic methods were compared with the gold standard culture test. RESULTS: Out of the total 330 TB suspects, 70.60% were males and 29.39% females. The most common complaint was of cough with sputum (88.18%), chest pain (70.21%), fever (55.15%) and loss of appetite (43.03%). Upon examining the total sputum slides, 18.48 % were positive for acid fast bacilli. The smear positivity was 61/330 (18.48%) by standard methods and in proposed new method 43/330 (13.03%). Sensitivity of the standard and proposed new method smear microscopy was 58.25% and 40.07% respectively and specificity was 99.55% in both the methods. CONCLUSION: Same day smear microscopy for diagnosing tuberculosis by a proposed new method of smear examination in the case of suspected tuberculosis seems not a promising step towards improving the quality of sputum smear examination. The results of sensitivity and specificity of the two approaches were not similar. More than eighty per cent responded in favour of same day sputum delivery system and getting result on same day. This study can be confirmed on larger scale and preference of patients can be examined in peripheral laboratory also before taking it up for consideration in the national tuberculosis programme.
INTRODUCTION: A large number of tuberculosis cases are continuously being reported from India and other developing countries leading to high morbidity and mortality. In spite of many newer tests available for diagnosing a case of tuberculosis, smear microscopy of sputum is still the preferred test under programmatic conditions. The current national and international guidelines recommend two sputum smear examinations in two days for diagnosing cases of tuberculosis, which is time-consuming, tedious, needs multiple visits, leading to high dropout of infectious cases. In the background of existing limitations of smear microscopy, we attempted to complete the diagnosis of tuberculosis on same day by serial collection of the spot sputum specimen and analyze its advantages, feasibility and viability. MATERIAL & METHODS: The study was undertaken by the Department of Microbiology, Lala Ram Sarup Institute of Tuberculosis and Respiratory Diseases during May 2010 to April 2011. Sputum specimens were collected from 330 randomly selected tuberculosis suspects who attended OPD of hospital, patients submitted spot and home collected morning sputum sample in a standard method and spot and additional spot sputum (X- spot) collected one hour after the first spot sample as per the proposed front loading method. All the samples received were stained by acid fast Ziehl-Neelsen (ZN) stain and examined on the same day. The sputum sample was pooled and cultured in Lowenstein Jensen (LJ) media in duplicate set of bottles. The results of two different microscopic methods were compared with the gold standard culture test. RESULTS: Out of the total 330 TB suspects, 70.60% were males and 29.39% females. The most common complaint was of cough with sputum (88.18%), chest pain (70.21%), fever (55.15%) and loss of appetite (43.03%). Upon examining the total sputum slides, 18.48 % were positive for acid fast bacilli. The smear positivity was 61/330 (18.48%) by standard methods and in proposed new method 43/330 (13.03%). Sensitivity of the standard and proposed new method smear microscopy was 58.25% and 40.07% respectively and specificity was 99.55% in both the methods. CONCLUSION: Same day smear microscopy for diagnosing tuberculosis by a proposed new method of smear examination in the case of suspected tuberculosis seems not a promising step towards improving the quality of sputum smear examination. The results of sensitivity and specificity of the two approaches were not similar. More than eighty per cent responded in favour of same day sputum delivery system and getting result on same day. This study can be confirmed on larger scale and preference of patients can be examined in peripheral laboratory also before taking it up for consideration in the national tuberculosis programme.
Authors: N Selvakumar; Vanaja Kumar; S Balaji; S Prabuseenivasan; R Radhakrishnan; Gomathi Sekar; V Chandrasekaran; T Kannan; Aleyamma Thomas; S Arunagiri; Puneet Dewan; Soumya Swaminathan Journal: PLoS One Date: 2015-03-04 Impact factor: 3.240