ICD 10 Coding Alert

Question: The indication of my provider’s report details the patient having both diarrhea and colitis. Do I assign codes to both conditions, or is only one code used in this case? And if I do code the diarrhea, do I use R19.7 or K59.1?

New Jersey Subscriber

Answer: First, you can determine the difference between the two diarrhea codes — R19.7 (Diarrhea, unspecified) and K59.1 (Functional diarrhea) — by looking at the code groups they are assigned under. Code K59.1 describes an intestinal condition characterized by its frequent recurrence, whereas R19.7 describes a symptom. For unspecified colitis, you will report K52.9 (Noninfective gastroenteritis and colitis, unspecified).

However, your job isn’t done just yet. While this coding scenario may seem relatively straightforward on the surface, it’s one you’ve got to be especially careful with. That’s because while diarrhea is typically a symptom of colitis, the coding guidelines provided by AHA Coding Clinic will actually instruct you to report R19.7 as the sole diagnosis.

Refresher: AHA Coding Clinic (Q4, 2018) includes guidance on Excludes1 reporting by instructing you to “assign only the code referenced in the Excludes1 note.”

So, for this diagnostic scenario, you will not be reporting K52.9, despite the fact that it seems to be more specific, and perhaps even the underlying cause, of the patient’s diarrhea.