Question: Montana Subscriber Answer: You are on the right coding path. First, report 50590 (Lithotripsy, extracorporeal shock wave) for the extracorporeal shock wave lithotripsy (ESWL). You'll report 592.0 (Calculus of kidney) as the diagnosis. This represents a renal pelvic stone, which your urologist most likely manipulated from the ureter into the renal pelvis. Next, report 52330 (Cystourethroscopy [including ureteral catheterization]; with manipulation, without removal of ureteral calculus) for the stone manipulation. Append modifier 59 (Distinct procedural service) to show the payer that this is a distinctly separate procedure from the ESWL. For this procedure, use a diagnosis of 592.1 (Calculus of ureter). You should report this second code because the stone manipulation is a distinct separate procedure using a separate technique unrelated to the ESWL of the stone.