Gastroenterology Coding Alert

Loose bowel movement might tell you more than meets the eye.

If a patient comes to your office reporting an episode of diarrhea, your physician may need to validate its real cause before providing treatment. Often, a bacterium called Clostridium difficile (C. difficile) could set off symptoms ranging from diarrhea to life-threatening inflammation of the colon.

While the cause of diarrhea is not identified in most patients because they get well without or with minor treatment, your practice should still be wary of the real origin of this symptom. Learn the ways to quickly recognize, diagnose, and report diarrhea with this expert advice.

Background: The ICD-9-CM manual defines diarrhea as:

• Abnormal frequency and fluidity of feces.
• Increased liquidity or decreased consistency of feces, such as running stool; fecal consistency is related to the ratio of water-holding capacity of insoluble solids to total water, rather than the amount of water present; diarrhea is not hyperdefecation or increased fecal weight
• Passage of loose, unformed stools
• A condition of frequent and watery bowel movements.

Don't Stop With Only Symptom Codes

The major symptom of intestinal infection due to C. difficile (008.45, Intestinal infection due to clostridium difficile) is diarrhea (787.91), although you'll also see abdominal pain (789.0) and sometimes fever (780.60). During this episode, a person becomes colonized with C. difficile spores, which make their way to the lower intestinal tract where they multiply and produce toxins that damage the colon and cause colitis. This episode most often occurs after a course of antibiotics has eliminated the usual bacterial flora of the colon allowing the relatively resistant C. difficile organism to flourish, says Michael Weinstein, MD, a gastroenterologist in Washington, D.C., and former member of the AMA's CPT® Advisory Panel. The toxin damage would manifest as diarrhea -- an increase in the frequency of bowel movements or a decrease in the form of stool. Some people with this infection even proceed to develop toxic megacolon (556.9, Ulcerative colitis unspecified), a dilation of the intestine.

Gastroenterologists who see a patient with active diarrhea may order a test for C. difficile infection through a stool study to identify the toxins produced by the bacteria. You would report the culture typing with the relatively new code 87493 (Infectious agent detection by nucleic acid [DNA or RNA]; Clostridium difficile, toxin gene[s], amplified probe technique), which debuted in 2010.

Prior to 2010, if your lab performed an amplified probe culture technique, you had to report 87149 (Culture, typing; identification by nucleic acid [DNA or RNA] probe, direct probe technique, per culture or isolate, each organism probed).

Because payers sometimes scrutinize not otherwise specified (NOS) codes more carefully and require extra documentation, having a specific code can enhance coverage for a test. "In fact, payers sometimes stop covering non-specific codes if utilization becomes too high," explains Michael Longacre, associate director of corporate reimbursement for BD, a medical technology company in New Jersey. This new code makes billing and claims processing much more efficient for C. difficile testing by amplified probe technique.

Keep To The Requisites

Usually, culture typing would occur in an independent laboratory. Your gastroenterologist would then read the result, and prepare a report. This means the laboratory does the technical component and the physician performs the professional component. If this is the case, you should append modifier TC to 87493 to indicate technical component, and modifier 26 to describe professional component.

On the other hand, if you're billing ICD-9 diagnosis code 008.45 on your claim, you must have documentation in your patient's medical record by the treating physician that a patient's diarrhea or toxic megacolon (if she developed this condition) is due to C. difficile. Sometimes, you will find that positive laboratory tests alone are insufficient.