Accurate diagnosis codes, or ICD-10-CM codes, are essential for establishing medical necessity, as they provide payers with a full picture of the patient's condition and support the physician's rationale for medical decision making.
In addition to condition diagnosis codes, status codes may indicate additional parameters affecting the rationale for a patient’s treatment or diagnostic testing and/or screening. These codes can be found in Chapter 23: Factors Influencing Health Status and Contact with Health Services (Z codes) of the ICD-10-CM manual. Code families that may relate to factors affecting rationale in oncology include, but are not limited to:
• Z15.0 - Z15.068 Genetic susceptibility to malignant neoplasms
• Z17.0 – Z17.421 Estrogen and other hormones factor status
• Z19.1, Z19.2 Hormone sensitivity or resistance status
• Z79.0 – Z79.891 Long term drug therapies
• Z80.0 – Z80.8 Family history of malignant neoplasms
• Z85.00 – Z85.89, Z86.000 – Z86.018 Personal history of malignant neoplasms, in-situ, and benign neoplasms
• Z90.01 – Z90.89 Absence of organs (i.e., breast, cervix, uterus)
• Z92.21 - Z92.3, Z92.850 – Z92.86 Personal history of drug therapy, irradiation, cellular and gene therapy
Stay up to date with oncology related diagnosis code changes for 2026 with ASCO’s 2026 ICD-10-CM
update resource.