Internal Medicine Coding Alert

Tip: Count the number of body systems involved to make the right choice.

Summertime is here, which means many of your patients will be spending more time outdoors. If a patient presents to your office with complications following a bee sting, how do you know whether to report an allergic reaction or something more serious, such as anaphylaxis? Consider the following case, then check out our expert's advice on how to handle similar situations.

Scenario: A 62-year-old woman develops generalized hives after a bee sting. She suddenly starts wheezing, so her husband brings her to your physician for treatment.

Identify the Reaction Reason

Your first thought might be to assign an allergic reaction diagnosis for the patient " but that's not your best choice in this case. Although allergic reactions are a type of anaphylaxis, grouping them together when it's time to code will not only result in the wrong ICD-9 code, but will also undermine the severity of the encounter from the payer's perspective.

Difference: Allergic responses involve local or general reaction to one body system, such as the skin. Anaphylactic shock, by contrast, affects multiple body systems, says Jeffrey Linzer, Sr., MD, MICP, FAAP, FACEP, associate professor of pediatrics and emergency medicine at Emory University School of Medicine in Atlanta.

"By definition, anaphylaxis syndrome is an explosive multisystem immune reaction," Linzer says. Generally, skin and respiratory symptoms appear first, but cardiac and gastrointestinal problems may also develop.

Explanation: The patient who sees your physician presents with initial symptoms of allergic reaction (995.3, Allergy, unspecified), hives (708.0, Allergic urticaria), and wheezing (786.07). Because the symptoms involved multiple body systems (skin and respiratory), you'll report a more specific anaphylaxis diagnosis, such as 995.0 (Certain adverse effects not elsewhere classified; other anaphylactic shock), instead of individual symptoms.

Additional: Before submitting the claim with 995.0 as the only diagnosis, consider the primary reason for the encounter " the bee sting. In the case of anaphylaxis due to insect bites, the venom triggers the reaction. Therefore, list 989.5 (Toxic effect of other substances, chiefly nonmedicinal as to source; venom) as the primary diagnosis and 995.0 as secondary. Reporting 995.0 without 989.5 would omit the reason for the shock.

Finally, add E905.3 (Venomous animals and plants as the cause of poisoning and toxic reactions; hornets, wasps and bees) to identify the source of anaphylactic syndrome. Some payers might not accept external cause codes, but including E905.3 gives a more complete picture of the situation.

Include E/M Code as Documentation Allows

Assuming the internist injected the patient with an antigen mix to treat the condition, you'll need to code for that service. Report 95130 (Professional services for allergen immunotherapy in prescribing physicians office or institution, including provision of allergenic extract; single stinging insect venom) for the injection.

You might also be able to report an E/M code for the encounter. Diagnoses 989.5, 995.0, and E905.3 help support medical necessity for the antigen injection. Complete documentation of the patient's condition should allow you to submit the appropriate E/M code from the 99201-99215 series.

Remember: Append modifier 25 (Significant, separately identifiable evaluation and management service by the same physician on the same day of the procedure or other service) to the E/M code to show the E/M and injection were separate services. Your final claim should include:

• 95130 for the antigen injection
• A choice from 99201-99215 for the E/M service
• Modifier 25 appended to the E/M code
• Diagnoses 989.5, 995.0, and E905.3 linked to 95130.