<prompt> All are true about CBD stones exceptAssociated with GB stonesPrimary stones are usually brownLaboratory values may be normal in one third cases of choledocholithiasisRetained stones are discovered after 2 years of cholecystectomy  <response>: Choledocholithiasis CBD stones are classified by point of origin Found in 6-12 of patients with GB stones Retained stones discovered within 2 years of cholecystectomy Recurrent stones detected 2 years following cholecystectomy Ref : Sabiston 20th edition Pgno :1494 