An Evaluation Study on X Ray Screening and Sputum Smear Microscopy as Diagnostic Tests for Tuberculosis Among the Presumptive TB Cases in Rural Area of Thiruvallur District.

Introduction: Tuberculosis (TB) is a major public health problem, especially in rural areas with limited healthcare access. While sputum smear microscopy remains the gold standard for TB diagnosis, it may fail to detect subclinical cases. The findings from this study would provide valuable insights into the reliability of these diagnostic tools and help in improving TB detection and management. Objectives:1. To estimate the prevalence of TB among presumptive cases in the study population. 2. To compare the diagnostic accuracy of chest X-ray and sputum smear microscopy in detecting TB among presumptive cases. Methods: This is a cross-sectional study was conducted on presumptive TB patients for a period of one year (August 2023 - 2024). Simple Random Sampling was employed to select the study participants. The sample size was 384. Sputum smear microscopy and chest X ray was done among all the study participants. Based on the result , diagnostic accuracy of chest X ray and sputum smear was determined. Results: Among 384 study participants, (56.8%) were males and (43.2%) were females. Their mean age was (50.99 + 3.84 years). Among the presumptive cases (57.5%) were diagnosed of having Tb. A total of 221 (133 males, 88 females) were diagnosed of having Tb with sputum smear microscopy. In the study, sensitivity and specificity of Xray as a diagnostic tool was found to be (89.14%) and (33.74%) respectively. The positive predictive value and negative predictive values were (64.59%) and (69.62%) respectively. The study also showed the positive likelihood ratio of 1.32. Conclusion: The study concluded that the sensitivity of Chest Xray in detecting Tb is high but specificity is low. Low specificity of Chest Xray can be attributed to the non-specific x-ray patterns and difficulty in interpretation. Chest Xray remains a useful adjuvant test and as screening tool in diagnosis of Tb to guide further patient management.