Question: Louisiana Subscriber Answer: Zevalin is a monoclonal antibody, and CPT does say chemotherapy administration codes are correct for "certain monoclonal antibodies." But you should not report chemo admin codes for Zevalin therapy. What to do: "Code 79403 is specific for radioimmunotherapy with radioactive materials attached to monoclonal antibodies," states AMA's CPT Assistant (September 2005). If you bear the cost of the drug, you also should report A9543 (Yttrium Y-90 ibritumomab tiuxetan, therapeutic, per treatment dose, up to 40 millicuries). Note that A9543 is specific to therapeutic use (as opposed to A9542 [Indium In-111 ibritumomab tiuxetan, diagnostic, per study dose, up to 5 millicuries], which is specific to diagnostic use and often paired with 78804 [Radiopharmaceutical localization of tumor or distribution of radiopharmaceutical agent(s); whole body, requiring 2 or more days imaging]). Check coverage policy: