Revenue Cycle Insider

Lasering in on the location can help you choose the correct code.

Coding for stones in a patient’s urinary tract can be a complicated task due to the varying anatomical locations and the diverse terminologies providers use. These complexities can result in inaccuracies, affecting claim reimbursements.

Look at some frequently asked questions (FAQs) — and the correlating answers — about kidney stones to always submit clean claims in your urology practice.

Question 1: Does the location of a stone matter? Are stones coded differently based on where they are found in the body?

Answer: Yes, the stone’s location does matter. Each section for coding stones or calculi corresponds to a specific anatomical location within the urinary tract. The coding is differentiated based on the precise location of the stones. Look at the list below:

• 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)

Question 2: If a urologist performed a percutaneous nephrolithotomy (PCNL) procedure, created their own access while performing the dilation, and ultimately removed a 1.9 cm stone, am I able to report more than one code?

Answer: For the procedures you described, you would submit code 50080 (Percutaneous nephrolithotomy or pyelolithotomy, lithotripsy, stone extraction, antegrade ureteroscopy, antegrade stent placement and nephrostomy tube placement, when performed, including imaging guidance; simple (eg, stone[s] up to 2 cm in single location of kidney or renal pelvis, nonbranching stones)) for the PCNL procedure. However, you should not separately report 50436 (Dilation of existing tract, percutaneous, for an endourologic procedure including imaging guidance (eg, ultrasound and/or fluoroscopy) and all associated radiological supervision and interpretation, with postprocedure tube placement, when performed) or 50437 (… including new access into the renal collecting system) for the dilation procedure.

Take note: National Correct Coding Initiative (NCCI) edits bundle both 50436 and 50437 codes with 50080 and 50081 (… complex (eg, stone[s] > 2 cm, branching stones, stones in multiple locations, ureter stones, complicated anatomy). Unless your urologist performed the dilation in a distinctly separate way from the PCNL procedure, you should not unbundle the codes, even though the bundles carry a modifier indicator of “1.” If the urologist performed dilation on the contralateral side (separate location), you might be able to report the PCNL and dilation access codes separately using modifier 59 (Distinct procedural service) or modifier XU (Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service).

Question 3: Will a patient’s symptoms change the code choice when it comes to coding for kidney stones?

Answer: Yes, the patient’s symptoms can affect the code choice. If the urologist suspects the presence of renal colic, which is a pain typically linked to kidney stones or blockages in the urinary tract caused by stones, the provider will use imaging tests to confirm and diagnose renal colic. ICD-10-CM code N23 (Unspecified renal colic) would be appropriate. However, if the urologist is unsure that a stone is causing the pain, use a code based on the location of the pain. These codes might include:

• M54.50 (Low back pain, unspecified)
• R10- (Abdominal and pelvic pain)
• R52 (Pain, unspecified)

Also, if the patient exhibits hematuria, a symptom frequently associated with kidney stones, this symptom also needs to be coded in the claim. In these cases, you would select from one of the following options:

• R31.0 (Gross hematuria) if the blood in the urine is visible
• R31.1 (Benign essential microscopic hematuria) for frequent and heavy hematuria that is only visible under a microscope
• R31.21 (Asymptomatic microscopic hematuria) for hematuria that is only visible under a microscope and that is not related to another, more serious condition
• R31.29 (Other microscopic hematuria)
• R31.9 (Hematuria, unspecified)

Question 4: How should imaging for kidney stones be coded?

Answer: This depends on which method of imaging the provider used.

Radiologists can use abdominal X-rays to identify stones within the urinary tract. The specific abdominal X-ray code for the procedure will be determined based on the number of views taken:

• 74018 (Radiologic examination, abdomen; 1 view)
• 74019 (… 2 views)
• 74021 (… 3 or more views)

However, abdominal X-rays may not show all stones, which is where CT scans can offer a better view. You’ll assign one of the following codes based on whether the radiologist uses contrast material with the procedure:

• 74176 (Computed tomography, abdomen and pelvis; without contrast material)
• 74177 (… with contrast material(s))
• 74178 (… without contrast material in one or both body regions, followed by contrast material(s) and further sections in one or both body regions)

Remember: Be sure to review the provider’s documentation and confirm whether the provider conducted a CT scan of the patient’s abdomen and/or pelvis during the encounter. The CT scans of the abdomen and pelvis are represented with a single code rather than individual codes for each anatomical region.

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