Can't speak from experience, but my encoder shows the below when I look up 'synagis.' Hopefully, someone can give you advice.
90378
Respiratory syncytial virus, monoclonal antibody, recombinant, for intramuscular use, 50 mg, each
Lay Description
Code 90378 identifies the respiratory syncytial virus (RSV) recombinant monoclonal antibody for intramuscular use, 50 mg, each. This humanized monoclonal antibody (IgG) gives protection against the respiratory syncytial virus and is injected once a month during the RSV season. Passive immunity is achieved for a short period as the antibodies received are circulated through the body. The recipient's immune system is not stimulated to build its own antibodies. Report this code with the appropriate administration code.
Notes
Section Notes - 90281-90399 Immunoglobulin Products - (90281-90399)
Immunoglobulin Products
INCLUDES:
Immune globulin product only
Immune globulins/antitoxins/various isoantibodies, and monoclonal antibodies:
Anti-infective
Broad-spectrum
Code also:
Code also administration (90772, 90774, 90775)
Code also:
Code also (96365-96368, 96372, 96374-96375)