ICD-10 Coding for the Flu

The five “Ws” about the flu.

It is that time of year again – flu season, which occurs in the fall and winter in the United States, stretching from early October until May.

For me, it was a new experience in 2018, as I got my first flu shot! I had been diagnosed as a very small child with an egg allergy, so getting the flu shot was contraindicated. I always had to be very careful during flu season, and I tried avoiding public locations and people who were sick.

The Centers for Disease Control and Prevention (CDC) since have made some changes to its recommendations, and people who do not have documented reactions to eggs (and people who have only experienced hives as a reaction) can now get the flu shot. If you have an egg allergy and have had major reactions, the CDC recommends that you be immunized in a medical setting, supervised by personnel who can address any reactions.

Now to the five W’s:

Who Should Be Immunized?

All people six months and older should be vaccinated. Children require two doses to be fully immunized. Older adults may require a high-dose immunization to assist their immune system.

 What Vaccine Will Be Administered?

The types of flu that are prevalent for 2019-2020 are:

• influenza B Victoria viruses have caused the most lab-confirmed flu diagnoses
• influenza A H1N1 viruses

Where Can You Get Vaccinated?

The vaccine is available at local pharmacies, clinics, doctors’ offices, public health offices, etc. There are many free clinics looking to prepare the public to be proactive for flu season. This preventative service is included in many health plans as a covered service.

 When Should You Be Vaccinated?

You should be vaccinated by the end of October. The CDC states that it takes two weeks for the body’s immune system to fully respond and be fully protected.   It is not too late to get vaccinated as the peak season is from December through February, but influenza can be contracted throughout the year.

 Why Should You Be Vaccinated?

As of February 4, 2020, the CDC has reported 15 million flu cases nationwide for the 2019-2020 flu season which resulted in 140,000 hospitalizations and 8,200 deaths in the U.S.

The Associated ICD-10-CM Codes  

When a patient presents for immunization, the ICD-10-CM code is Z23 (Encounter for immunization). Please note that this code is not specific to the influenza immunization. That specificity will be identified by the associated HCPCS code for the actual vaccine.

For patients who have contracted the flu, the default code is J11.1 (Influenza due to the unidentified influenza virus with other respiratory manifestations). A specific code requires the following information to code the disease specifically:

• Type
  • A/H5N1/novel A/avian/swine (J09.X2)
  • Novel H1N1 (J10.1)
• Associated Manifestations
  • Digestive (enteritis, gastroenteritis)
  • Encephalopathy
  • Myocarditis
  • Respiratory (laryngitis, pharyngitis, etc.)
  • Otitis media
  • Pneumonia
  • Other specified

For conditions that have manifestation, the code will vary depending upon the virus type. This information can be added to your physician query.

Consider getting your vaccination so you can avoid taking paid time off just for feeling under the weather.  I am so happy to be vaccinated this year!   

Read Laurie Johnson’s related article “How to Code the Flu in ICD-10“.