Z28 — Immunization not carried out and underimmunization status
Not billable
Is Z28 billable?
No — Z28 is a non-billable header code. Z28 groups more specific codes and cannot be submitted on a claim. A valid ICD-10-CM code must be reported at the highest level of specificity available in its branch. Select one of the 17 billable codes beneath Z28.
Billable codes under this header
- Z28.1Immunization not carried out because of patient decision for reasons of belief or group pressure
- Z28.9Immunization not carried out for unspecified reason
- Z28.01Immunization not carried out because of acute illness of patient
- Z28.02Immunization not carried out because of chronic illness or condition of patient
- Z28.03Immunization not carried out because of immune compromised state of patient
- Z28.04Immunization not carried out because of patient allergy to vaccine or component
- Z28.09Immunization not carried out because of other contraindication
- Z28.20Immunization not carried out because of patient decision for unspecified reason
- Z28.21Immunization not carried out because of patient refusal
- Z28.29Immunization not carried out because of patient decision for other reason
- Z28.39Other underimmunization status
- Z28.81Immunization not carried out due to patient having had the disease
- Z28.82Immunization not carried out because of caregiver refusal
- Z28.83Immunization not carried out due to unavailability of vaccine
- Z28.89Immunization not carried out for other reason
- Z28.310Unvaccinated for COVID-19
- Z28.311Partially vaccinated for COVID-19
Z28 at a glance
| Code | Z28 |
|---|---|
| Description | Immunization not carried out and underimmunization status |
| Billable | No — header code |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Code also
Two codes may be needed to describe the condition fully. Whether Z28 is sequenced first depends on the reason for the encounter.
- , if applicable, encounter for immunization safety counseling (Z71.85)
Includes
Conditions classified to Z28.
- vaccination not carried out
What codes fall under Z28? (6)
- Z28.0Immunization not carried out because of contraindicationnot billable
- Z28.1Immunization not carried out because of patient decision for reasons of belief or group pressure
- Z28.2Immunization not carried out because of patient decision for other and unspecified reasonnot billable
- Z28.3Underimmunization statusnot billable
- Z28.8Immunization not carried out for other reasonnot billable
- Z28.9Immunization not carried out for unspecified reason
How long has Z28 existed?
Z28 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.