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	—
Z28.01	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	✓
Z28.02	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	—
Z28.03	Immunization not carried out because of immune compromised state of patient	✓
Z28.3	Underimmunization status	—
Z28.04	Immunization not carried out because of patient allergy to vaccine or component	✓
Z28.8	Immunization not carried out for other reason	—
Z28.09	Immunization not carried out because of other contraindication	✓
Z28.9	Immunization not carried out 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	✓
Z28.29	Immunization not carried out because of patient decision for other reason	✓
Z28.31	Underimmunization for COVID-19 status	—
Z28.39	Other underimmunization status	✓
Z28.81	Immunization not carried out due to patient having had the disease	✓
Z28.82	Immunization not carried out because of caregiver refusal	✓
Z28.83	Immunization not carried out due to unavailability of vaccine	✓
Z28.89	Immunization not carried out for other reason	✓
Z28.310	Unvaccinated for COVID-19	✓
Z28.311	Partially vaccinated for COVID-19	✓

More free billing tools: all ICD-10 categories · ICD-10 search · denial codes · Medicare fees

Informational only, not coding or medical advice. Verify against the official ICD-10-CM (FY2026) and your payer's guidelines.

Code the diagnosis right