Oncology & Hematology Coding Alert

Question: What is the most appropriate ICD-10-CM code for CHEK2 mutation? As the mutation increases the hereditary risk of breast cancer, would you use a family history code? Or, as the mutation is not as likely to cause breast cancer as the BRCA1 or BRCA2 gene, is there another code I should use?

AAPC Forum Participant

Answer: In this encounter, you would not use a family history code such as Z84.81 (Family history of carrier of genetic disease) as the primary code. Use of this code would be more appropriate if the patient had a family member who was tested and found to be a carrier of the gene, though you could use the code as an additional diagnosis if that is supported by the documentation.

As the patient was the subject of the testing, and as the patient had been diagnosed with having the mutation, the best primary code to use under the circumstances would be Z15.01 (Genetic susceptibility to malignant neoplasm of breast). Additionally, per the ICD-10-CM notes for subcategory Z15.0, you would also “Code first, if applicable, any current malignant neoplasm (C00-C75, C81-C96)” and an additional code, if applicable, “for any personal history of malignant neoplasm (Z85.-).”