In Siddha system, one of the most important and most needed methods of diagnosis is Naadi, which is based on the three humors. To determine the usefulness of naadi examination in detecting vippuruthi/puttru and to improve the detection of early stages of vippuruthi.297 cases were included in this study. Among 295 cases confirmed 120 cancer cases and 177 non cancer cases were selected and randomized for the detection of Naadi in a blinded manner. Then the examined Naadi were compared for similarities and variations. The data was statistically analysed using Wilson score method for diagnostic accuracy and sensitivity and specificity of the agreement between investigators was determined. The sensitivity was obtained at 87.4% depicting that Nadi’s examination for the trihumoural alteration correctly classified as true cancer-positive cases. But low specificity (5.7%) showed a low rate of classifying cancer-negative cases. The agreement between two investigators based on Kaba Nadi alone was 79% (kappa value=0.79) which was statistically significant at p = 0.036. However, the study showed specificity (5.7%) corresponding to low rate of classifying cancer-negative cases.