Grade 1: reflux into the distal ureter

Grade 2: reflux into the proximal renal collecting system without dilatation

Grade 3: reflux into the renal calices with mild dilatation/tortuosity of the ureter, renal pelvis and calices.

Grade 4: reflux into the renal calices with moderate dilatation/tortuosity of the ureter, renal pelvis and calices with obliteration of the fornices but maintainence of the papillary impressions.

Grade 5: reflux into the renal calices with gross dilatation/tortuosity of the ureter, renal pelvis and calices. The papillary impressions will be lost in the majority of the calices. This type is typically treated with surgery.