ICD-10-CM · Z00–Z99Billable
ICD-10-CM Code Z23
Encounter for immunization
Source: CMS ICD-10-CM FY2026Effective Reviewed by the D3rx Clinical Billing Team
Diagnosis information
Billable
Yes
Valid for claim submission
Chapter
Z00–Z99
Factors influencing health status and contact with health services
Risk adjustment
None
Not risk-adjustable (V28)
Documentation & coding notes
- Z23 is a billable/specific ICD-10-CM code — it can be reported as a primary or secondary diagnosis when the documentation supports it. Code to the highest level of specificity the record allows.
- As a Z-code (factor influencing health status), Z23 is often a secondary code that explains the reason for an encounter or a relevant status. Sequencing depends on why the patient presented; some payers restrict Z-codes as a first-listed diagnosis.
- Always verify the code against the current ICD-10-CM Official Guidelines and the payer's coverage policy before submitting — coverage, medical necessity edits, and sequencing rules vary by payer.
Related Z00–Z99 codes
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Medical coding disclaimer
ICD-10-CM codes and descriptions shown are from the CMS FY2026 official code set and HCC mappings from the CMS-HCC V28 model (payment year 2026), shown for educational reference. Official Guidelines, payer coverage, medical-necessity edits, and sequencing rules vary. Always verify with the current ICD-10-CM Official Guidelines and the payer before submitting claims. D3rx is not responsible for coding or billing outcomes.