Urology Coding Alert

Question: Can you use N13.2 if a patient has both renal and ureteral stones?

Florida Subscriber

Answer: No, you cannot use N13.2 (Hydronephrosis with renal and ureteral calculous obstruction) because the patient must also have hydronephrosis before you can use this code. Even though the term “calculous” in the descriptor for N13.2 indicates that this diagnosis code pertains to a condition involving stones, this code only applies when the stone is accompanied by hydronephrosis, a condition that causes the kidneys to swell due to urine buildup. If hydronephrosis is caused by a renal/ureteral stone that’s obstructing flow, then you’ll turn to N13.2.

Remember you shouldn’t report both N13.2 and N20.0 (Calculus of kidney) when the urologist sees patients with hydronephrosis due to a kidney stone; there is an Excludes1 note following N20 that instructs you to report N13.2. If a patient has both renal and ureteral stones, you’ll use N20.2 (Calculus of kidney with calculus of ureter) along with N21.1 (Calculus in urethra) to report both conditions.

Helpful tip: ICD-10-CM guideline A.12.a states an Excludes1 note is a “pure exclusion note” and that you cannot code the two linked conditions together because they cannot exist together. So, if your provider documents both a condition coded to N20.- and N13.2, you would only report N13.2. Or to put it another way, per ICD-10-CM Coding Clinic Volume 5, Number 4 (2018), you should “assign only the code referenced in the Excludes1 note.”

Lindsey Bush, BA, MA, CPC, Development Editor, AAPC