Urology Coding Alert

Get to know the terms your urologist might use, and which apply to each code.

Your urologist is likely to see patients with stones affecting the urinary tract, and whether they’re located in the kidney, bladder, ureter, or another location, you’ve got dozens of choices when it comes to diagnosis coding. Selecting the most accurate ICD-10-CM code will be key to proving medical necessity for your physician’s services, but it can be easy to get lost in the sea of options.

Check out these three tips to accurately select the right code every time for stones.

1. Pin Down Location First

Your first step in selecting a code will be to pinpoint where the stone was located. Also referred to as a calculus (one stone) or calculi (multiple stones), these can occur in various locations along the urinary tract, so you can’t assume that they’re all reported as kidney stones or bladder stones.

Check out this list of the most common locations, along with the corresponding code family:

• N20.0 (Calculus of kidney)
• N20.1 (Calculus of ureter)
• N20.2 (Calculus of kidney with calculus of ureter)
• N20.9 (Urinary calculus, unspecified)
• N21.0 (Calculus in bladder)
• N21.1 (Calculus in urethra)
• N21.8 (Other lower urinary tract calculus)
• N21.9 (Calculus of lower urinary tract, unspecified)
• N22 (Calculus of urinary tract in diseases classified elsewhere)

You’ll note that the final code on this list (N22) requires you to first code the underlying disease. For instance, if the patient has gout, you’ll report a primary code from the M1A-M10 series, followed by N22.

2. Understand Other Terms for Location Terminology

If you read through the above list with more questions than answers, that may mean that your urologist uses different terminology in their reports than the ones reflected in the ICD-10-CM code set. Check out these pointers to better correlate your physician’s potential terminology with the right codes.

• Nephrolithiasis (N20.0)
• Renal calculus (N20.0)
• Renal stone (N20.0)
• Staghorn calculus (N20.0)
• Stone in kidney (N20.0)
• Calculus of the uteropelvic junction (N20.1)
• Ureteric stone (N20.1)
• Calculus in diverticulum of the bladder (N21.0)
• Urinary bladder stone (N21.0)

If you see terminology in the physician’s report of a stone or calculus but the location doesn’t correspond to these terms or the ones in the code descriptors, query the urologist for more information about location so you can select the right code.

3. Scrutinize How N13.2 Fits in

When you’re scanning the ICD-10-CM code set, you’re sure to notice N13.2 (Hydronephrosis with renal and ureteral calculous obstruction). Because the descriptor refers to “calculous,” it’s clear that this diagnosis code describes a condition that includes a stone. However, there are some key differences to note between this code and the main stone codes listed above.

First, you’ll never report N13.2 for a basic renal or ureteral stone. Instead, this code 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.

Plus, keep in mind that you should not report both N13.2 and N20.0 when the urologist sees patients with hydronephrosis due to a stone. The ICD-10-CM code book clearly lists an Excludes2 note following N20 that excludes you from reporting this code with N13.2.

Therefore, if you see a patient with hydronephrosis and renal/ ureteral calculous obstruction, you’ll report just N13.2.

Torrey Kim, Contributing Writer, Raleigh, N.C.