Tissue No of Sample Negative Samples Positive Samples Prevalence Lung            13 9 4 25.0% Lymph nodes 5 3 2 40.0% Total 18 12 6 33.3% P value=1.00, Relative risk=0.7692 (0.1997-2.963) at 95% confidence interval

Table 2: Ziehl Neelson staining test of heat treated samples.