DxCodebookFY2027 · Oct 1, 2026 – Sep 30, 2027

Z23 diagnosis code · Billable category · FY2027

Z23 Encounter for immunization

  • Billable
  • Not CC/MCC
  • POA exempt

Z23 ICD-10 code: a billable diagnosis code in FY2027; the category has no subdivisions.

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. Z23 Encounter for immunization
CC / MCC
Neither
MS-DRG
795, 951
HCC V28
–
POA
Exempt
Code Editor
Unacceptable PDX
Index entries
4

Instructions

At Z23

Notes

  • procedure codes are required to identify the types of immunizations given

Code first

  • any routine childhood examination

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

  • Immunizationencounter for → Z23
  • Prophylacticvaccination → Z23
  • Vaccination (prophylactic)encounter for → Z23
  • Admission (for)prophylactic (measure)vaccination → Z23

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

Medicare grouping and edits

CMS files for Z23
CC / MCCNeither
Appendix BMDC 15 Newborns and Other Neonates with Conditions Originating in Perinatal Period, MS-DRG 795 (Normal Newborn…); MDC 23 Factors Influencing Health Status and Other Contacts with Health Services, MS-DRG 951 (Other Factors Influencing Health Status…)
Code EditorUnacceptable principal diagnosis
POAExempt
HCC V28–

CMS: MS-DRG v44 (Appendix B, C), MCE v44, POA list FY2027, 2027 Initial ICD-10-CM Mappings. What the rows mean.

Hierarchy