Pediatric Coding Alert

Question: Can I use Z23 as the primary code for a flu vaccination encounter?

Codify Subscriber

Answer: If the patient is coming in for only the vaccine, most payers accept Z23 (Encounter for immunization) as the primary code. However, check with your payer and your state’s regulations. For example, in some states, Medicaid requires you report Z00.- as the primary code and Z23 as the secondary code if the patient’s is receiving vaccines from the Vaccines for Children (VFC) stock.

That being said, do not report Z23 as the primary diagnosis code when the pediatrician provided additional services during the visit, such as an evaluation and management (E/M). You’ll see by the Z23 ICD-10 entry it says, “Code first any routine childhood examination.” See also Guideline I.C.21.c.2, which states, “Code Z23 is for encounters for inoculations and vaccines … code Z23 may be used as a secondary code if the inoculation is given as a routine part of preventative health care, such as a well-baby visit.” Remember also to use procedure codes to report the administration and type of immunization.