Gastroenterology Coding Alert

Question: We often see patients who have allergies or intolerance regarding things like gluten and lactose. Should we code intolerance the same as allergies?

Tennessee Subscriber

Answer: No, food allergies are not the same as food intolerances. Basically stated, “food allergies, such as allergies to nuts or shellfish, are caused by a problem with your immune system. Food sensitivities or intolerances, such as reactions to wheat or milk, are caused by a problem with your digestive system,” according to the U.S. Department of Health and Human Services (HHS) (Source: www.womenshealth.gov/healthy-eating/food-allergies-and-sensitivities).

The difference between the two is critical from a clinical perspective. An allergic food reaction can be severe or life-threatening, whereas food intolerance symptoms are generally less serious. From a coding perspective, this means you have to look to different chapters of ICD-10 to find the codes you need to describe a patient’s food allergy or sensitivity status.

Food allergy codes are easily found as they have their own subcategory of codes — Z91.01- (Food allergy status). Food intolerance codes, however, are a little more difficult to track down, though many of them can be found in the Diseases of the Digestive System chapter and coded to the K90.4- (Other malabsorption due to intolerance) ICD-10 subcategory.

Patients who suffer from lactose intolerance cannot break down sugar in dairy products due to a deficiency in the enzyme lactase. Because of this, the code is categorized in the Endocrine, Nutritional and Metabolic Diseases chapter of ICD-10 and not in the Diseases of the Digestive System chapter. This means you should use a code that is specific to lactose intolerance from the E73.- (Lactose intolerance) codes. It also means you should not use Z91.011 (Allergy to milk products). This is reinforced by the Excludes1 note to Z91.011, which tells you should not code Z91.011 with a code from E73.-.

Both gluten sensitivity and celiac disease share common characteristics: in both, the body responds negatively to the gluten protein, which is found in food made using cereal grains such as wheat, oats, rye, and barley. But the two conditions differ in their effects on the human body, with gluten sensitivity causing minor, short-term symptoms such as stomachaches and bloating, and celiac disease causing such long-term health problems as malabsorption and bowel damage.

That’s why you must choose carefully between two different diagnosis codes in situations where a patient is affected by an adverse reaction to gluten. You’ll use K90.0 (Celiac disease) if your gastroenterologist documents it, and K90.41 (Non-celiac gluten sensitivity) for gluten sensitivity that is less serious. Just be sure to look for the celiac and non-celiac designations.

Expert coding tip: The K90.4- (Other malabsorption due to intolerance) codes have an Excludes2 instruction that allows you to code both celiac and non-celiac gluten sensitive enteropathy and lactose intolerance (K90.0, K90.41, and E73.-) together when your GI physician documents them.