So, you need a diagnosis code for a flu shot. But what ICD-10 code should you use? Under ICD-9 you would have used V70.0, V20.2 or V04.81 depending on the coding situation but hold on to your hats ICD-10 has made this simple. Regardless if you are coding for commercial insurance or Medicare there’s only one code you
need to use Z23 – Encounter for Immunization Actually under ICD-10, you simply use code Z23 regardless of how many or what types of vaccines are given to a patient. Be aware that Z23 includes a note that states: “Code first any routine childhood examination.” So when you give the flu vaccine at a well-child visit, an age appropriate ICD-10 code for a routine child health examination needs to be reported first, then Z23. Make sure you check with your carriers and how they want the flu shot billed. Oh and don’t forget the admin code.