To improve diagnostic accuracy, the ABCD rule of lesion screening is widely used which is based on asymmetry (A), border (B), color (C), and differential structure (D) measuring. • A total dermatoscopic value (TDV) results from the calculation TDV = A·1,3 + B·0,1 + C·0,5 + D·0,5 • This score contributes to the differentiation between benign and malignant lesions: 1,00 – 4,75 – benign skin lesion 4,75 – 5,45 – suspicious More than 5,45 – melanoma Asymmetry A – Asymmetry of Shape, Structure, and Color. The skin lesion is divided into four regions, and there is symmetry inspected across x or y-axis. If asymmetry is only by one axis, it gives 1 point and if on both axes there are 2 points calculated. So for shape, structure, and color, there can be 6 points maximum.