2026 ICD-10-CM Diagnosis Code Z28.21Immunization not carried out because of patient refusal

ICD-10-CM Codes›Z00–Z99›Z20-Z29›Z28

ICD-10-CM Z28.21
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Z28.21 is a billable ICD-10-CM diagnosis code for immunization not carried out because of patient refusal. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is not accepted as a principal diagnosis by the Medicare Code Editor and exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under No immunization or underimmunization.

Code Identity

ICD-10-CM Code
Z28.21
Billable Status
Yes — Valid for Submission
Code Describes
Immunization not carried out because of patient refusal
Short Description
Immunization not carried out because of patient refusal
Same as the full description in the CMS dataset.
Parent Code
Z28.2
Immunization not carried out because of patient decision for other and unspecified reason

Code Classification

ChapterZ00–Z99Factors influencing health status and contact with health services
SectionZ20-Z29Persons with potential health hazards related to communicable diseases
CategoryZ28Immunization not carried out and underimmunization status
This CodeZ28.21Immunization not carried out because of patient refusal

Code EditsBilling

Medicare Code Editor checks that affect claim validity for Z28.21.

Unacceptable principal diagnosis
There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

Present on Admission (POA)Billing

Z28.21 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • BCG vaccination declined
  • Booster meningitis B vaccination declined
  • First meningitis B vaccination declined
  • Hepatitis A vaccination declined
  • Hepatitis B immunization declined
  • Human papillomavirus vaccination declined
  • Human respiratory syncytial virus vaccination declined
  • Inactivated whole SARS-CoV-2 antigen vaccine declined
  • Influenza A virus subtype H1N1 vaccination declined
  • Influenza vaccination declined
  • Measles, mumps and rubella vaccination declined
  • Meningitis B vaccination declined
  • Meningitis C immunization declined
  • Meningococcal vaccination declined
  • Pertussis vaccination declined
  • Pneumococcal vaccination declined
  • SARS-CoV-2 antigen vaccine declined
  • SARS-CoV-2 DNA plasmid encoding spike protein vaccine declined
  • SARS-CoV-2 mRNA vaccine declined
  • SARS-CoV-2 non-replicating viral vector vaccine declined
  • SARS-CoV-2 recombinant spike protein antigen vaccine declined
  • SARS-CoV-2 vaccination declined
  • SARS-CoV-2 virus-like particle antigen vaccine declined
  • Second dose of inactivated whole SARS-CoV-2 antigen vaccine declined
  • Second dose of SARS-CoV-2 mRNA vaccine declined
  • Second dose of SARS-CoV-2 non-replicating viral vector vaccine declined
  • Second dose of SARS-CoV-2 recombinant spike protein antigen vaccine declined
  • Second dose of SARS-CoV-2 virus-like particle antigen vaccine declined
  • Second meningitis B vaccination declined
  • Tetanus vaccination declined by patient
  • Vaccination declined
  • Vaccination hesitancy by parent
  • Vaccination hesitancy by patient
  • Vaccine declined by patient
  • Varicella zoster vaccination declined by patient

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Immunization
      • not done (not carried out)
        • because (of)
          • patient refusal

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR FAC017
No immunization or underimmunization
Default principal diagnosis: inpatient No · outpatient Yes

Convert Z28.21 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
V64.06 No vaccination-pt refuse
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About Z28.21Overview

Is Z28.21 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report immunization not carried out because of patient refusal on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Can Z28.21 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because immunization not carried out because of patient refusal describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

Is Z28.21 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for immunization not carried out because of patient refusal on inpatient claims.

What is the ICD-9 equivalent of Z28.21?

Under the General Equivalence Mappings, immunization not carried out because of patient refusal converts to ICD-9-CM V64.06 (no vaccination-pt refuse). The mapping is approximate, so confirm the match fits the documentation.