ICD10BillableValid for clinical use

ICD-10 Code Z23: Encounter for immunization

Z23 is a billable ICD-10 diagnosis code used to classify Encounter for immunization in medical records and claims. You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records. ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Factors influencing health status and contact with health services (Z00-Z99).

Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026

What is this code?

ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Factors influencing health status and contact with health services (Z00-Z99).

When is it used?

  • May be used when a clinician documents encounter for immunization in a patient's medical record.
  • May appear in hospital records, claims, referrals, and clinical documentation.
  • This code can be used as a clinically usable diagnosis entry in standardized coding workflows.

What it does not mean

  • A code alone does not explain severity, treatment plan, or outcome.
  • A medical code should not be treated as a substitute for a doctor's diagnosis or advice.

Code hierarchy

chapter
21Factors influencing health status and contact with health services (Z00-Z99)
block
Z20-Z29Persons with potential health hazards related to communicable diseases
currentZ20-Z29

Official coding notes

Applicable to
  • any routine childhood examination
Code first
  • any routine childhood examination
Code also
  • , if applicable, encounter for immunization safety counseling (Z71.85)

Where you may see this code

You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.

Related specialists

General Physician

Coverage-related procedures and services

CPT 90702high
DIPHTHERIA AND TETANUS TOXOIDS ADSORBED (DT) WHEN ADMINISTERED TO INDIVIDUALS YOUNGER THAN 7 YEARS, FOR INTRAMUSCULAR USE
Source: CMS coverage guidance
CPT 90759high
HEPATITIS B VACCINE (HEPB), 3-ANTIGEN (S, PRE-S1, PRE-S2), 10 MCG DOSAGE, 3 DOSE SCHEDULE, FOR INTRAMUSCULAR USE
Source: CMS coverage guidance
CPT 90743high
HEPATITIS B VACCINE (HEPB), ADOLESCENT, 2 DOSE SCHEDULE, FOR INTRAMUSCULAR USE
Source: CMS coverage guidance
CPT 90746high
HEPATITIS B VACCINE (HEPB), ADULT DOSAGE, 3 DOSE SCHEDULE, FOR INTRAMUSCULAR USE
Source: CMS coverage guidance
CPT 90739high
HEPATITIS B VACCINE (HEPB), CPG-ADJUVANTED, ADULT DOSAGE, 2 DOSE OR 4 DOSE SCHEDULE, FOR INTRAMUSCULAR USE
Source: CMS coverage guidance
CPT 90740high
HEPATITIS B VACCINE (HEPB), DIALYSIS OR IMMUNOSUPPRESSED PATIENT DOSAGE, 3 DOSE SCHEDULE, FOR INTRAMUSCULAR USE
Source: CMS coverage guidance

Coding guidelines

Compatibility

Legacy and official ICD code match exactly.
Legacy codes
Z23

Common synonyms

Encounter for immunization

Frequently asked questions

Code details

CodeZ23
SystemICD10
Display nameEncounter for immunization
ChapterFactors influencing health status and contact with health services (Z00-Z99)
BlockPersons with potential health hazards related to communicable diseases

Flags

BillableYes
Valid clinical useYes

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

Index terms

Matched terms
Admission(for)ImmunizationProphylacticVaccination(prophylactic)

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.

ICD-10 Code Z23 for Encounter for immunization | HealthAssure