HCPCS Level II code M0221 describes administration of the monoclonal antibody combination tixagevimab and cilgavimab for pre-exposure prophylaxis in eligible adults and pediatric patients (age ≥12 years and ≥40 kg) with no known SARS‑CoV‑2 exposure; the service includes the injection and post-administration monitoring provided in the home or residence (including a home temporarily designated provider-based during the COVID‑19 public health emergency), and is billed as an outpatient injectable prophylaxis service for immunocompromised patients or those with contraindications to COVID‑19 vaccination.