Oncology & Hematology Coding Alert

Question: Recently, a patient came into the oncologist’s office for a mammogram to have a tumor in her breast looked at. I coded Z12.3 but it was rejected. What did I do wrong?

Montana Subscriber

Answer: For this circumstance the code you must use is Z12.31 (Encounter for screening mammogram for malignant neoplasm of breast). The addition of one number makes all the difference.

If you look up Z12.3 in the ICD-10-CM guidebook, you will see a little red symbol to the left of it. This symbol shows ‘5th’ which indicates a fifth symbol must be used. Typically, the fifth symbol is used to highlight etiology, anatomic site, severity, or other clinical details.

In your situation, coding Z12.3 (Encounter for screening for malignant neoplasm of breast) will always be incorrect without the addition of a fifth character. This is because the fifth character specifies what kind of screening took place. Without the fifth character, your original code has the potential to be confused with Z12.39 (Encounter for other screening for malignant neoplasm of breast) — another code under Z12.3 requires a fifth character and is billed differently.

The big takeaway is to keep your eyes open. The ICD-10-CM guidebook makes use of many identifying symbols to help you determine the best code to use. Some symbols indicate a fourth, sixth, or seventh symbol is required. In this case, the ‘5th’ symbol indicates specifically a mammogram was conducted which helps your practice accurately report codes without being rejected.