Z28: Immunization not carried out and underimmunization status
Codes under Z28 (Immunization not carried out and underimmunization status). A ✓ marks a billable (fully specified) code; category codes without a ✓ are not billable on their own.
| Code | Description | Billable |
|---|---|---|
| Z28.0 | Immunization not carried out because of contraindication | — |
| Z28.0 | Immunization not carried out because of contraindication | — |
| Z28.01 | Immunization not carried out because of acute illness of patient | ✓ |
| Z28.01 | Immunization not carried out because of acute illness of patient | ✓ |
| Z28.1 | Immunization not carried out because of patient decision for reasons of belief or group pressure | ✓ |
| Z28.1 | Immunization not carried out because of patient decision for reasons of belief or group pressure | ✓ |
| Z28.02 | Immunization not carried out because of chronic illness or condition of patient | ✓ |
| Z28.02 | Immunization not carried out because of chronic illness or condition of patient | ✓ |
| Z28.2 | Immunization not carried out because of patient decision for other and unspecified reason | — |
| Z28.2 | Immunization not carried out because of patient decision for other and unspecified reason | — |
| Z28.03 | Immunization not carried out because of immune compromised state of patient | ✓ |
| Z28.03 | Immunization not carried out because of immune compromised state of patient | ✓ |
| Z28.3 | Underimmunization status | — |
| Z28.3 | Underimmunization status | — |
| Z28.04 | Immunization not carried out because of patient allergy to vaccine or component | ✓ |
| Z28.04 | Immunization not carried out because of patient allergy to vaccine or component | ✓ |
| Z28.8 | Immunization not carried out for other reason | — |
| Z28.8 | Immunization not carried out for other reason | — |
| Z28.09 | Immunization not carried out because of other contraindication | ✓ |
| Z28.09 | Immunization not carried out because of other contraindication | ✓ |
| Z28.9 | Immunization not carried out for unspecified reason | ✓ |
| Z28.9 | Immunization not carried out for unspecified reason | ✓ |
| Z28.20 | Immunization not carried out because of patient decision for unspecified reason | ✓ |
| Z28.20 | Immunization not carried out because of patient decision for unspecified reason | ✓ |
| Z28.21 | Immunization not carried out because of patient refusal | ✓ |
| Z28.21 | Immunization not carried out because of patient refusal | ✓ |
| Z28.29 | Immunization not carried out because of patient decision for other reason | ✓ |
| Z28.29 | Immunization not carried out because of patient decision for other reason | ✓ |
| Z28.31 | Underimmunization for COVID-19 status | — |
| Z28.31 | Underimmunization for COVID-19 status | — |
| Z28.39 | Other underimmunization status | ✓ |
| Z28.39 | Other underimmunization status | ✓ |
| Z28.81 | Immunization not carried out due to patient having had the disease | ✓ |
| Z28.81 | Immunization not carried out due to patient having had the disease | ✓ |
| Z28.82 | Immunization not carried out because of caregiver refusal | ✓ |
| Z28.82 | Immunization not carried out because of caregiver refusal | ✓ |
| Z28.83 | Immunization not carried out due to unavailability of vaccine | ✓ |
| Z28.83 | Immunization not carried out due to unavailability of vaccine | ✓ |
| Z28.89 | Immunization not carried out for other reason | ✓ |
| Z28.89 | Immunization not carried out for other reason | ✓ |
| Z28.310 | Unvaccinated for COVID-19 | ✓ |
| Z28.310 | Unvaccinated for COVID-19 | ✓ |
| Z28.311 | Partially vaccinated for COVID-19 | ✓ |
| Z28.311 | Partially vaccinated for COVID-19 | ✓ |
Frequently asked questions
What is ICD-10-CM code Z28?
Z28 is an ICD-10-CM category covering Immunization not carried out and underimmunization status. It contains 44 more specific diagnosis codes, 34 of which are billable.
Is Z28 a billable code?
No — Z28 is a category header and isn't billable on its own. Code to the highest level of specificity using one of its subcodes (for example Z28.0 — Immunization not carried out because of contraindication). 34 of the 44 codes under Z28 are billable.
What codes fall under Z28?
Z28 includes Z28.0, Z28.0, Z28.01, Z28.01, Z28.1, plus 39 more. See the full list with descriptions and billable status above.
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Informational only, not coding or medical advice. Verify against the official ICD-10-CM (FY2026) and your payer's guidelines.
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