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ICD-10-CM 2027

ICD-10 code for antineoplastic immunotherapy

Z51.12

Encounter for antineoplastic immunotherapy

✓ Billable / specific

From the official ICD-10-CM alphabetic index entry “Immunotherapy (encounter for) › antineoplastic”. Page updated September 29, 2026.

About coding antineoplastic immunotherapy

The ICD-10-CM code for antineoplastic immunotherapy is Z51.12 (Encounter for antineoplastic immunotherapy).

Within Z51.1 (encounter for antineoplastic chemotherapy and immunotherapy), Z51.12 is specifically for encounter for antineoplastic immunotherapy. Related codes cover chemotherapy (Z51.11).

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), DRG 837 (Chemotherapy with Acute Leukemia as Secondary Diagnosis or with High Dose Chemotherapy Agent with MCC, relative weight 4.7124) and 5 more, 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.

Common questions about antineoplastic immunotherapy ICD-10 codes

What is the ICD-10 code for antineoplastic immunotherapy?

Z51.12 — Encounter for antineoplastic immunotherapy.

Is Z51.12 billable?

Yes. Z51.12 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can Z51.12 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict Z51.12 as a principal diagnosis.

Is Z51.12 a CC or MCC?

No. Z51.12 is neither a CC nor an MCC under MS-DRG v44.0.