ICD-10-CM 2027 diagnosis code
Z51.0Encounter for antineoplastic radiation therapy
Z51.0 is a valid, billable ICD-10-CM code for encounter for antineoplastic radiation therapy. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.
Looking up by condition? See ICD-10 code for Radiotherapy session.
Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data
About Z51.0
Z51.0 is the ICD-10-CM diagnosis code for encounter for antineoplastic radiation therapy. It belongs to category Z51 (encounter for other aftercare and medical care), block Z40-Z53 (Encounters for other specific health care) and chapter 21 (factors influencing health status and contact with health services). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.
Within Z51 (encounter for other aftercare and medical care), Z51.0 is specifically for encounter for antineoplastic radiation therapy. Related codes cover antineoplastic chemotherapy and immunotherapy (Z51.1), palliative care (Z51.5), desensitization to allergens (Z51.6), other specified aftercare (Z51.8) and sepsis aftercare (Z51.A).
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 826 (Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Major O.R. Procedures with MCC, relative weight 4.7581), DRG 827 (Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Major O.R. Procedures with CC, relative weight 2.3896), DRG 828 (Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Major O.R. Procedures without CC/MCC, relative weight 1.6955), DRG 829 (Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Other Procedures with CC/MCC, relative weight 3.1281), DRG 830 (Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Other Procedures without CC/MCC, relative weight 1.4859) and DRG 849 (Radiotherapy, relative weight 2.5857), in MDC 17 (Myeloproliferative Diseases and Disorders, Poorly Differentiated Neoplasms), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
It is exempt from present-on-admission (POA) reporting, so no POA indicator is required.
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Before ICD-10, this condition was coded in ICD-9-CM as V58.0 (encounter for radiotherapy).
Notes that apply from higher levels
Instructions written at a parent level also apply to Z51.0.
Broader instructions also apply from Z40-Z53 Encounters for other specific health care and Chapter 21: Factors influencing health status and contact with health services.
Alphabetic index entries
6 entriesTerms in the official ICD-10-CM index that lead to Z51.0.
- Admission (for) › aftercare › radiation therapy (antineoplastic)
- Admission (for) › radiation therapy (antineoplastic)
- Encounter (with health service) (for) › radiation therapy (antineoplastic)
- Maintenance (encounter for) › antineoplastic radiation therapy
- Radiation › therapy, encounter for
- Radiotherapy session
MS-DRG v44.0 grouping
All DRGs →Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.
MDC 17 · Myeloproliferative Diseases and Disorders, Poorly Differentiated Neoplasms
- 826Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Major O.R. Procedures with MCCRW 4.7581
- 827Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Major O.R. Procedures with CCRW 2.3896
- 828Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Major O.R. Procedures without CC/MCCRW 1.6955
MDC 17 · Myeloproliferative Diseases and Disorders, Poorly Differentiated Neoplasms
MDC 17 · Myeloproliferative Diseases and Disorders, Poorly Differentiated Neoplasms
ICD-9-CM equivalent
Converter →- V58.0Encounter for radiotherapyexact
From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about Z51.0
Is Z51.0 billable?
- Yes. Z51.0 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Z51.0 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict Z51.0 as a principal diagnosis.
Is Z51.0 a CC or MCC?
- No. Z51.0 is neither a CC nor an MCC under MS-DRG v44.0.
What DRG does Z51.0 group to?
- Z51.0 is used in the MS-DRG v44.0 logic for MS-DRG 826 (Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Major O.R. Procedures with MCC), MS-DRG 827 (Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Major O.R. Procedures with CC), MS-DRG 828 (Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Major O.R. Procedures without CC/MCC), MS-DRG 829 (Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Other Procedures with CC/MCC), MS-DRG 830 (Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Other Procedures without CC/MCC) and MS-DRG 849 (Radiotherapy). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.