Patient admission/encounter chiefly for administration of antineoplastic chemotherapy, immunotherapy and radiation therapy

If a patient admission/encounter is chiefly for the administration of chemotherapy, immunotherapy or external beam radiation therapy for the treatment of a neoplasm, assign code Z51.0, Encounter for antineoplastic radiation therapy, or Z51.11, Encounter for antineoplastic chemotherapy, or Z51.12, Encounter for antineoplastic immunotherapy as the first-listed or principal diagnosis.

If the reason for the encounter is more than one type of antineoplastic therapy, code Z51.0 and codes from subcategory Z51.1 may be assigned together, in which case one of these codes would be reported as a secondary diagnosis. The malignancy for which the therapy is being administered should be assigned as a secondary diagnosis.

If a patient admission/encounter is for the insertion or implantation of radioactive elements (e.g., brachytherapy) the appropriate code for the malignancy is sequenced as the principal or first-listed diagnosis. Code Z51.0 should not be assigned.