HCPCS Code J9355: Injection, Trastuzumab, Excludes Biosimilar, Per 10 mg

Learn about the correct use of HCPCS Code J9355 for trastuzumab injection, documentation requirements, and proper billing practices.

Use Code

## **What is trastuzumab injection?** Trastuzumab injection is an IV infusion primarily used to treat HER2 positive breast cancer, including early breast cancer and metastatic breast cancer. This therapy works by targeting cancer cells, preventing their growth and spread, and is often administered as part of adjuvant therapy or alongside other chemotherapy drugs. In some cases, Trastuzumab may also be indicated for gastric cancer patients or for tumors in overlapping sites that require careful management. Healthcare providers must fully understand the patient’s treatment history, including prior trastuzumab infusion sessions, trastuzumab ANNS, or other drug regimens, to ensure medical necessity and safe administration. Diagnostic tests, such as in situ hybridization, may be used to confirm eligibility. Proper use of the code ensures clear differentiation from biosimilar alternatives, as this code specifically excludes biosimilar versions, and supports accurate clinical documentation for both hormone receptor negative and positive cases.

## **Documentation requirements** Accurate documentation is essential for J9355 administration to support medical necessity, safe dosing, and correct billing. Key items to include: - Record the malignant neoplasm diagnosis, including tumor type, location, and tumor size. - Note if the patient is node negative and document hormone receptor status. - Specify that trastuzumab excludes biosimilar 10 mg is being administered. - Include prior therapies or trastuzumab qyyp if applicable. - Document whether treatment is for early breast cancer, metastatic breast cancer, or part of adjuvant chemotherapy. - Record IV infusion details, including schedule, dose, and any modifications based on patient response. - Include any tumor thresholds or tumor greater criteria impacting therapy decisions.

## **Billing requirements** Proper billing for J9355 ensures reimbursement and compliance with payer guidelines: - Bill using the specific code J9355 for trastuzumab injection, excludes biosimilar. - Confirm the patient’s diagnosis and document all relevant malignant neoplasm details. - Include tumor characteristics such as tumor size, node negative status, and hormone receptor results. - Document therapy type, whether adjuvant chemotherapy, trastuzumab qyyp, or for early/metastatic breast cancer. - Record each IV infusion session, including dose, duration, and clinical notes. - Note any prior therapies or combination regimens to avoid claims denials.

## **Other relevant keywords** - **Q5112**: Trastuzumab-dttb (biosimilar), per 10mg - **Q5114**: Trastuzumab-dkst (biosimilar), per 10mg - **Q5116**: Trastuzumab-qyyp (biosimilar), per 10mg - **J9306**: Pertuzumab, per 1mg