HCPCS Level II code S9500 represents a per diem administrative and professional service for home infusion antimicrobial therapy provided once every 24 hours. It captures non-drug components of at-home systemic antibiotic, antiviral, or antifungal treatment — specifically administrative coordination, professional pharmacy services, care coordination, and necessary supplies and equipment. Drugs and nursing visits for the infusion are billed separately, making S9500 a key code for separating clinical supply and oversight costs from medication and hands-on nursing fees.

This code matters nationally as home infusion grows as an alternative to inpatient care for selected infectious indications, enabling care continuity and potential cost efficiencies while requiring clear billing distinctions between services. Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare.

Readers will learn what S9500 covers clinically and administratively, which services are excluded (drugs and nursing visits), and how the code fits into home infusion service lines. The publication also summarizes common modifiers, payer coverage considerations, and benchmark and policy contexts relevant to home infusion per diem billing. Data not available in the input for specific taxonomies, ICD-10 pairings, and payer-specific reimbursement rates are noted where applicable.