Z28

Immunization not carried out and underimmunization status

Diagnosis reference

Nonbillable category

This entry is a category or subcategory. Choose the appropriate billable descendant based on the clinical documentation.

Effective periodOctober 1, 2026–September 30, 2027

SourceCMS ICD-10-CM order file

ClassificationDiagnosis · clinical modification

Related entries

Up to 30 descendants in this category

CODE	DESCRIPTION	TYPE
Z28.0	Immunization not carried out because of contraindication	Category
Z28.01	Immunization not carried out because of acute illness of patient	Billable
Z28.02	Immunization not carried out because of chronic illness or condition of patient	Billable
Z28.03	Immunization not carried out because of immune compromised state of patient	Billable
Z28.04	Immunization not carried out because of patient allergy to vaccine or component	Billable
Z28.09	Immunization not carried out because of other contraindication	Billable
Z28.1	Immunization not carried out because of patient decision for reasons of belief or group pressure	Billable
Z28.2	Immunization not carried out because of patient decision for other and unspecified reason	Category
Z28.20	Immunization not carried out because of patient decision for unspecified reason	Billable
Z28.21	Immunization not carried out because of patient refusal	Billable
Z28.29	Immunization not carried out because of patient decision for other reason	Billable
Z28.3	Underimmunization status	Category
Z28.31	Underimmunization for COVID-19 status	Category
Z28.310	Unvaccinated for COVID-19	Billable
Z28.311	Partially vaccinated for COVID-19	Billable
Z28.39	Other underimmunization status	Billable
Z28.8	Immunization not carried out for other reason	Category
Z28.81	Immunization not carried out due to patient having had the disease	Billable
Z28.82	Immunization not carried out because of caregiver refusal	Billable
Z28.83	Immunization not carried out due to unavailability of vaccine	Billable
Z28.89	Immunization not carried out for other reason	Billable
Z28.9	Immunization not carried out for unspecified reason	Billable

Use the complete reference

This reference does not reproduce the full tabular hierarchy, inclusion notes, Excludes1/2 notes, sequencing instructions, or seventh-character rules. Review the official tables and coding guidelines.

Open official CMS files

ICD-10-CM codes describe diagnoses. They do not have an independent Medicare PFS reimbursement amount, and billability alone does not establish coverage.