ICD 10 Coding Alert

Question: The doctor has diagnosed one of our patients as having a milk allergy. I used an E73.- code, but my colleague says the payer is going to deny the claim. If not E73.-, then how should I code the allergy?

Wisconsin Subscriber

Answer: If the documentation clearly states the patient has a milk allergy and not an intolerance, code Z91.011 (Allergy to milk products). You’ll also see an Excludes1 note attached to Z91.011 instructing not to code from E73.-. (Lactose intolerance). Brushing up on the etiology will help you understand how to code these types of conditions.

A food allergy affects the immune system, and the reaction can be life-threatening depending on severity. It is considered a digestive disease, and you can therefore find the corresponding codes in ICD-10 chapter 11: Diseases of the Digestive System. A food intolerance generally only affects the digestive system and is usually much less serious. Patients with lactose intolerance, for example, lack the enzyme lactose and therefore cannot break down the sugar in dairy products. Codes for this are found in ICD-10 Chapter 4: Endocrine Nutritional and Metabolic Diseases.

It’s not too uncommon to hear “lactose intolerance” and “milk allergy” used interchangeably, because many people misunderstand the difference. Your practitioners will know the difference though, so any unclear notes are probably examples of incomplete notetaking. Always query the provider if you think essential information is missing or unclear.