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ICD-10-CM 2027 diagnosis code

Z28Immunization not carried out and underimmunization status

Not billable — use a more specific code

Z28 is a header code, so it can't be reported by itself. Choose one of the 6 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About Z28

Z28 is the ICD-10-CM diagnosis code for immunization not carried out and underimmunization status. It belongs to block Z20-Z29 (persons with potential health hazards related to communicable diseases) and chapter 21 (factors influencing health status and contact with health services). It is a header code, so it can't be reported by itself; one of its 6 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: Z28.0 (contraindication), Z28.1 (pressure), Z28.2 (reason), Z28.3 (status), Z28.8 (reason) and Z28.9 (reason).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under Z28

Coding notes

IncludesFurther defines the content of the category
  • vaccination not carried out
Code alsoTwo codes may be needed; sequencing depends on circumstances
  • , if applicable, encounter for immunization safety counseling (Z71.85)

Notes that apply from higher levels

Instructions written at a parent level also apply to Z28.

Broader instructions also apply from Chapter 21: Factors influencing health status and contact with health services.

Codes whose notes reference Z28

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about Z28

Is Z28 billable?

No. Z28 is a header code. Report one of its more specific subcodes instead.