The Centers for Medicare and Medicaid Services (CMS) has provided
updated guidance for institutional providers for coding claims for vaccine administration when the vaccination is the only service billed on the claim.
The effective date is for claims with a date of service beginning April 13, 2026.
Below is the modified CMS guidance. The new coding requirements are in the bold and italicized text:
The following diagnosis code must be reported. If the sole purpose for the visit is to receive a vaccine or if a vaccine is the only service billed on a claim, the applicable following diagnosis code may be used.
ICD-10-CM Diagnosis Code = Z23 -- Description - Encounter for Immunization
NOTE: ICD-10-CM diagnosis code Z23 is to be used for all encounters for preventive vaccine immunizations, including COVID-19 immunizations.
The following condition code must be reported on institutional claims when diagnosis code Z23 is required for a vaccination.
Condition Code = A6 -- Description - Vaccine / Medicare 100% Payment
All claims must have the appropriate diagnosis code, procedure, and admin code to process correctly.
Additional vaccine billing guidance can be found at the AHCA/NCAL
#GetVaccinated resources page.