The following individual variables were independent predictors of CBD stone: age (OR: 1.0251, 95% CI: 1.0160, 1.0344, P <0.001), gender (OR: 1.4553, 95% CI: 1.0601, 1.9979, P=0.021), bilirubin (OR: 1.0131 95% CI: 1.0090, 1.0172, P <0.001), ALP (OR: 1.0037, 95% CI: 1.0028, 1.0047, P<0.001), ALT (OR: 1.0009, 95% CI: 1.0003, 1.0014, P=0.001), CBD diameter on US (OR: 1.1327, 95% CI: 1.0758, 1.1927, P<0.001), and cholecystitis on US (OR: 1.5713, 95% CI: 1.1363, 2.1728), P=0.007) (Table 3). This evidence concerns the gene GPT and red-green color blindness.