ICD-10-CM 2027
ICD-10 code for encounter for vaccination
From the official ICD-10-CM alphabetic index entry “Vaccination (prophylactic) › encounter for”. Page updated September 29, 2026.
About coding encounter for vaccination
The ICD-10-CM code for encounter for vaccination is Z23 (Encounter for immunization).
Code first: any routine childhood examination.
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 795 (Normal Newborn, relative weight 0.2022) and DRG 951 (Other Factors Influencing Health Status, relative weight 0.5577), in MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period) and MDC 23 (Factors Influencing Health Status and Other Contacts with Health Services), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
Common questions about encounter for vaccination ICD-10 codes
What is the ICD-10 code for encounter for vaccination?
- Z23 — Encounter for immunization.
Is Z23 billable?
- Yes. Z23 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Z23 be used as a principal diagnosis?
- No. It is not acceptable as the principal diagnosis for an inpatient stay; it may be reported as a secondary diagnosis.
Is Z23 a CC or MCC?
- No. Z23 is neither a CC nor an MCC under MS-DRG v44.0.