Z23
Encounter for immunization
This code does not map to a risk-adjusting HCC in the loaded models.
Coding notes
Excludes 1 never coded together · Excludes 2 may co-exist
any routine childhood examination
, if applicable, encounter for immunization safety counseling (Z71.85)
procedure codes are required to identify the types of immunizations given
Z codes represent reasons for encounters. A corresponding procedure code must accompany a Z code if a procedure is performed. Categories Z00-Z99 are provided for occasions when circumstances other than a disease, injury or external cause classifiable to categories A00-Y89 are recorded as 'diagnoses' or 'problems'. This can arise in two main ways: (a) When a person who may or may not be sick encounters the health services for some specific purpose, such as to receive limited care or service for a current condition, to donate an organ or tissue, to receive prophylactic vaccination (immunization), or to discuss a problem which is in itself not a disease or injury. (b) When some circumstance or problem is present which influences the person's health status but is not in itself a current illness or injury.
Official Guidelines for Z23
FY 2026 ›Sections that reference Z23
- I.C.21.c.2)Inoculations and vaccinations
Code Z23 is for encounters for inoculations and vaccinations. …
- I.B.3Code or codes from A00.0 through T88.9, Z00-Z99.8, U00-U85Conventions & general rules
The appropriate code or codes from A00.0 through T88.9, Z00-Z99.8, and U00-U85 must be used to identify diagnoses, symptoms, conditions, problems, complaints or other reason(s) for the …
- I.C.20.a.1)Used with any code in the range of A00.0-T88.9, Z00-Z99Chapter 20
An external cause code may be used with any code in the range of A00.0-T88.9, Z00-Z99, classification that represents a health condition due to an external cause. …
- IV.BCodes from A00.0 through T88.9, Z00-Z99, U00-U85Outpatient services
The appropriate code(s) from A00.0 through T88.9, Z00-Z99 and U00-U85 must be used to identify diagnoses, symptoms, conditions, problems, complaints, or other reason(s) for the …
- IV.EEncounters for circumstances other than a disease or injuryOutpatient services
… The Factors Influencing Health Status and Contact with Health Services codes (Z00- Z99) are provided to deal with occasions when circumstances other than a disease or injury are recorded as diagnosis or problems. …
Sections whose FY 2026 text names Z23, its Z23 category, or a range containing it — the chapter guidance above is the authoritative source.
Find Z23 in the alphabetic index
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