Gastroenterology Coding Alert

Question: What is the difference between 564.5, which is a covered diagnosis code for a colonoscopy with our carrier and 787.91, which is not?

Michigan Subscriber

Answer: There are many possible causes of diarrhea, including viruses, bacteria and drugs. The ICD-9 manual notes that functional diarrhea shows no detectable organic cause. It is also another term for irritable bowel syndrome (564.1), says Michael Weinstein, MD, a gastroenterologist in Washington, D.C., and a member of the American Medical Associations CPT advisory panel.

A patient with chronic diarrhea could be described with ICD-9 codes 787.91 (other symptoms involving digestive system, diarrhea), 564.1 (irritable colon) or 564.5 (functional digestive disorders, functional diarrhea), says Weinstein. Or if there is a known cause, it can be described by any of a hundred specific infections, diseases, or postoperative conditions.

The ICD-9 manual suggests that 787.91 should be used to report a change in bowel habits, not a longstanding condition. The manual also notes that 787.91 should not be used when a gastroenterologist has determined that the patient has a specific functional or other gastrointestinal disorder. But many gastroenterologists do use the two terms and two diagnosis codes interchangeably.

You are right that some carriers only list code 564.5 as a covered diagnosis code for colonoscopy (though many carriers do cover both 564.5 and 787.91). Carriers in New York, New Jersey, Pennsylvania and Oklahoma are among the carriers that only cover 564.5.

Because there really isnt much difference between the two codes, you might want to consider approaching the medical director of your local carrier and asking him or her to revise the carriers local medical review policy for colonoscopies to include 787.91 as a covered diagnosis for the procedure. In support of your request, you could include copies of the many carrier policies that do cover both ICD-9 codes.