HCPCS Level II code S9994 denotes lodging costs for a clinical trial participant and one caregiver/companion, covering nonmedical hotel or temporary accommodation expenses needed to enable trial participation. This code matters nationally as clinical trial support services increasingly affect patient access, trial enrollment, and payer coverage policies. Lodging coverage can reduce barriers for patients who must travel for investigational treatments or study visits, and clarity around use of S9994 influences plan design, prior authorization processes, and billing practices.

Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the code’s clinical and operational context, typical sites of service, and which payers commonly address lodging for trial participants. The publication outlines benchmarks and coverage patterns where available, notes common billing modifiers included in administrative guidance, and summarizes policy considerations affecting billing and patient access. It also highlights areas where data is limited and calls out where additional policy clarification may be needed. The focus is national in scope and intended for billing professionals, clinical trial administrators, and payer policy analysts seeking a clear, practical reference to S9994.