Z51.1Header code — not billable
Encounter for antineoplastic chemotherapy and immunotherapy
- Chapter
- 21. Factors influencing health status and contact with health services
- Category
- Z51
- Effective date
- October 1, 2026
Related codes in category Z51
Z51Encounter for other aftercare and medical careZ51.0Encounter for antineoplastic radiation therapyYesZ51.11Encounter for antineoplastic chemotherapyYesZ51.12Encounter for antineoplastic immunotherapyYesZ51.5Encounter for palliative careYesZ51.6Encounter for desensitization to allergensYesZ51.8Encounter for other specified aftercareZ51.81Encounter for therapeutic drug level monitoringYesZ51.89Encounter for other specified aftercareYesZ51.AEncounter for sepsis aftercareYes
Frequently asked questions
What is ICD-10 code Z51.1?
Z51.1 is an ICD-10-CM diagnosis code for Encounter for antineoplastic chemotherapy and immunotherapy.
Is Z51.1 a billable code?
No. Z51.1 is a category/header code, not billable on its own — use one of its more specific child codes instead.
What ICD-10-CM chapter is Z51.1 in?
Z51.1 falls under Chapter 21: Factors influencing health status and contact with health services.
When did Z51.1 become effective?
Z51.1 has been effective since October 1, 2026, per the CMS/CDC ICD-10-CM annual release.
What other codes are related to Z51.1?
Z51.1 belongs to category Z51, which includes 10 other codes — see the related codes list on this page.
ICD-10-CM data maintained by CDC/CMS (public domain). Always verify codes with authoritative sources before making coding or billing decisions.