The accurate diagnosis of COVID-19 is essential for effective disease management and control. This study evaluates the performance of diagnostic tests using sensitivity, specificity, and predictive values along with their 95% confidence intervals (CI), applying Bayes’ Rule to estimate the probability of an individual being COVID-positive based on specific symptoms. Data were collected during the second wave of COVID-19 in India, focusing on the National Capital Region (NCR), India, through a survey conducted via Google Forms. The study identifies common symptoms to predict COVID-19 and calculates the probability of a person being COVID-positive if they exhibit these symptoms. Furthermore, it demonstrates the utility of Bayesian methods [1][2] in enhancing diagnostic accuracy by synthesizing results from the tests. These findings underscore the importance of accurate diagnostic tools and symptom recognition in managing COVID-19 and provide valuable insights into the progression of the pandemic during its second wave in India.