DxCodebookFY2027 · Oct 1, 2026 – Sep 30, 2027

Category · FY2027

Z28 Immunization not carried out and underimmunization status

  • Header · not billable

Z28 is not billable. The category heads 17 billable codes in FY2027, grouped under 6 subdivisions.

Index → code

  • Underimmunization status → Z28.39
  • Delinquent immunization status → Z28.39
  • Lapsed immunization schedule status → Z28.39

Where it sits

  1. Chapter 21 Factors influencing health status and contact with health services (Z00-Z99)
  2. Z20-Z29 Persons with potential health hazards related to communicable diseases (Z20-Z29)
  3. Z28 Immunization not carried out and underimmunization status
Billable codes
17
Subdivisions
6
CC / MCC codes
0 / 0
HCC V28 codes
0
New FY2027
0
Index entries
43

Codes in Z28

  1. Z28.0
    Immunization not carried out because of contraindication
    Header
  2. Z28.01
    Immunization not carried out because of acute illness of patient
    BillableExempt
  3. Z28.02
    Immunization not carried out because of chronic illness or condition of patient
    BillableExempt
  4. Z28.03
    Immunization not carried out because of immune compromised state of patient
    BillableExempt
  5. Z28.04
    Immunization not carried out because of patient allergy to vaccine or component
    BillableExempt
  6. Z28.09
    Immunization not carried out because of other contraindication
    BillableExempt
  7. Z28.1
    Immunization not carried out because of patient decision for reasons of belief or group pressure
    BillableExempt
    Inclusion terms 1

    Inclusion terms

    • Immunization not carried out because of religious belief
  8. Z28.2
    Immunization not carried out because of patient decision for other and unspecified reason
    Header
  9. Z28.20
    Immunization not carried out because of patient decision for unspecified reason
    BillableExempt
  10. Z28.21
    Immunization not carried out because of patient refusal
    BillableExempt
  11. Z28.29
    Immunization not carried out because of patient decision for other reason
    BillableExempt
  12. Z28.3
    Underimmunization status
    Header
    Use additional code 5

    Use additional code

    • code, if applicable, to identify:
    • immunization not carried out because of contraindication (Z28.0-) Z28.0
    • immunization not carried out because of patient decision for other and unspecified reason (Z28.2-) Z28.2
    • immunization not carried out because of patient decision for reasons of belief or group pressure (Z28.1) Z28.1
    • immunization not carried out for other reason (Z28.8-) Z28.8
  13. Z28.31
    Underimmunization for COVID-19 status
    Header
    Notes 1

    Notes

    • These codes should not be used for individuals who are not eligible for the COVID-19 vaccines, as determined by the healthcare provider.
  14. Z28.310
    Unvaccinated for COVID-19
    BillableExempt
  15. Z28.311
    Partially vaccinated for COVID-19
    BillableExempt
  16. Z28.39
    Other underimmunization status
    BillableExempt
    Inclusion terms 2

    Inclusion terms

    • Delinquent immunization status
    • Lapsed immunization schedule status
  17. Z28.8
    Immunization not carried out for other reason
    Header
  18. Z28.81
    Immunization not carried out due to patient having had the disease
    BillableExempt
  19. Z28.82
    Immunization not carried out because of caregiver refusal
    BillableExempt
    Inclusion terms 2, Excludes1 1

    Inclusion terms

    • Immunization not carried out because of guardian refusal
    • Immunization not carried out because of parent refusal

    Excludes1

    • immunization not carried out because of caregiver refusal because of religious belief (Z28.1) Z28.1
  20. Z28.83
    Immunization not carried out due to unavailability of vaccine
    BillableExempt
    Inclusion terms 3

    Inclusion terms

    • Delay in delivery of vaccine
    • Lack of availability of vaccine
    • Manufacturer delay of vaccine
  21. Z28.89
    Immunization not carried out for other reason
    BillableExempt
  22. Z28.9
    Immunization not carried out for unspecified reason
    BillableExempt

Sources of each column.

Instructions

At Z28

Includes

  • vaccination not carried out

Code also

  • , if applicable, encounter for immunization safety counseling (Z71.85) Z71.85

Notes that also apply

Chapter 21 instructions (Notes 3): printed on the chapter 21 page.

Index entries

  • Delinquent immunization status → Z28.39
  • Lapsed immunization schedule status → Z28.39
  • Underimmunization status → Z28.39
  • Delinquent immunization statusCOVID-19 → Z28.31-
  • Underimmunization statusCOVID-19 → Z28.31-
  • COVID-19unvaccinated (for) → Z28.310
  • Unimmunizedfor COVID-19 → Z28.310
  • Unvaccinatedfor COVID-19 → Z28.310
  • COVID-19partially vaccinated (for) → Z28.311
  • Status (post)delinquent immunization → Z28.39
  • Status (post)lapsed immunization schedule → Z28.39
  • Status (post)underimmunization → Z28.39
  • Delay, delayedvaccination → Z28.9
  • Immunizationnot done (not carried out) → Z28.9
  • Vaccination (prophylactic)delayed → Z28.9
  • Status (post)delinquent immunizationCOVID-19 → Z28.31-
  • Status (post)underimmunizationCOVID-19 → Z28.31-
  • Underimmunization statusCOVID-19unvaccinated (for) → Z28.310
  • Immunizationpartialfor COVID-19 → Z28.311
  • Underimmunization statusCOVID-19partially vaccinated (for) → Z28.311
  • Vaccination (prophylactic)partialfor COVID-19 → Z28.311
  • Immunizationnot done (not carried out)because (of)acute illness of patient → Z28.01
  • Immunizationnot done (not carried out)because (of)chronic illness of patient → Z28.02
  • Immunizationnot done (not carried out)because (of)immune compromised state of patient → Z28.03
  • Immunizationnot done (not carried out)because (of)allergy to vaccine (or component) → Z28.04
  • Immunizationnot done (not carried out)because (of)contraindication NEC → Z28.09
  • Immunizationnot done (not carried out)because (of)group pressure → Z28.1
  • Immunizationnot done (not carried out)because (of)patient's belief → Z28.1
  • Immunizationnot done (not carried out)because (of)religious beliefs of patient → Z28.1
  • Immunizationnot done (not carried out)because (of)unspecified patient reason → Z28.20
  • Immunizationnot done (not carried out)because (of)patient refusal → Z28.21
  • Status (post)underimmunizationCOVID-19unvaccinated (for) → Z28.310
  • Status (post)underimmunizationCOVID-19partially vaccinated (for) → Z28.311
  • Immunizationnot done (not carried out)because (of)patient had disease being vaccinated against → Z28.81
  • Immunizationnot done (not carried out)because (of)caregiver refusal → Z28.82
  • Immunizationnot done (not carried out)because (of)guardian refusal → Z28.82
  • Immunizationnot done (not carried out)because (of)parent refusal → Z28.82
  • Immunizationnot done (not carried out)because (of)delay in delivery of vaccine → Z28.83
  • Immunizationnot done (not carried out)because (of)lack of availability of vaccine → Z28.83
  • Immunizationnot done (not carried out)because (of)manufacturer delay of vaccine → Z28.83

3 more, longer entries are not listed; the search box finds them by word.

NCHS Alphabetic Index. Index first, then the Tabular List.

Hierarchy