HCPCS code J9355: Trastuzumab injection, per 10 mg, non-biosimilar2026 Medicare rate & RVUs in Washington

CMS doesn’t publish an office rate for J9355 in Washington.

Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.

What J9355 covers

J9355 represents non-biosimilar trastuzumab, an intravenous monoclonal antibody used in treatment regimens for HER2-positive breast cancer and certain HER2-positive gastric or gastroesophageal junction cancers. Oncology practices and hospital outpatient departments commonly report the drug when it is administered as part of a treatment course. This code is for trastuzumab itself, not an antibody-drug conjugate or a subcutaneous trastuzumab combination.

CMS assigns status E, which excludes the drug from the physician fee schedule; when Medicare covers it, payment is made under another method. The HCPCS pricing method identifies it as a Part B drug generally paid using CMS quarterly ASP drug pricing files when covered. The Medicare contractor determines coverage. Each billing unit represents 10 mg of trastuzumab, so the administered dose is converted into 10 mg units. The drug code represents the medication, while a reportable infusion administration is a separate service.

This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.

Where J9355 pays more and less in Washington

How the J9355 rate is calculated

Each of J9355’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.

Payment rules and modifiers for J9355

J9355 has no global surgery period, no multiple-procedure, bilateral or assistant-at-surgery adjustment, and no professional/technical split. What changes the payment is where the service happens: the place of service on the claim decides whether Medicare pays the office or the facility rate.

J9355 compared with similar codes

How to choose

J9354Ado-trastuzumab emtansinePer 1 mg

J9354 is ado-trastuzumab emtansine, an antibody-drug conjugate. J9355 is non-biosimilar trastuzumab without that attached drug.

J9356Trastuzumab combinationPer 10 mg trastuzumab

J9356 is the subcutaneous trastuzumab and hyaluronidase product; J9355 represents intravenous trastuzumab.

J9358Fam-trastuzumab deruxtecanPer 1 mg

J9358 represents trastuzumab deruxtecan, a distinct antibody-drug conjugate, not trastuzumab alone.

Q5117Kanjinti injectionPer 10 mg

Q5117 identifies trastuzumab-anns, a biosimilar. J9355 is for trastuzumab excluding biosimilars.

Codes related to J9355

Related codes aren’t interchangeable: bill the code that matches the service performed.

Where these rates come from

FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.

CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027

Open CMS sourceHow we calculate rates