- History of (within 24 months prior to enrollment) of kidney, ureter, or bladder stones with clinically significant sequelae (e.g. (painless gross hematuria; pain with or without infection; hydronephrosis, etc); patients with otherwise stable non-occluding kidney stones regardless of stone type incidentally found in computed tomography (CT) scans are eligible; patients with prior history of uric acid stones are eligible regardless of time of onset