Commercial payers typically offer a streamlined, allinone approach: drugs are billed under the medical benefit; pharmacy services, supplies, and equipment are bundled into a predictable per diem; and nursing is billed separately. Because all components can be submitted on a single claim, commercial reimbursement creates a more efficient, aligned payment experience. Use this page to access quick code references, billing guidance, and practical tools that support accurate, timely reimbursement.
Commercial Billing & Coding Resources
National Coding Standard
This document, which is widely used by payers and providers throughout the United States, presents the HCPCS (Healthcare Common Procedure Coding System) per diem “S” codes as a comprehensive coding system for home infusion therapy claims and provides procedures for their use, information about what’s included in the home infusion per diem, and detailed coding examples for both typical and unusual claims scenarios that payers and providers are likely to encounter. It also includes procedures and examples for services provided in the Ambulatory Infusion Suite of the Home Infusion Therapy Provider (AIS).
Per Diem Definition
As related to reimbursement, the term “per diem” represents each day that a given patient is provided access to a prescribed therapy, beginning with the day the therapy is initiated and ending with the day the therapy is permanently discontinued. This definition is valid for per diem therapies of duration of up to and including every 72 hours. Therapies provided beyond this range (weekly, monthly, etc.) fall outside of the per diem structure, and should have separate reimbursement rates that are specified on a contractual or other basis.
Guide for Billing S-codes for HIT to Non-Medicare Payers
Members Only
Per HIPAA regulation, providers and payers must use national standard codes and conform to HCPCS and CPT® code descriptions which may not be changed. HCPCS per diem S-codes have descriptions which (1) specify what is included in payment for the code and (2) by exclusion specify what is coded, billed, and paid for separately.
NHIA Model Contract
Members Only
The NHIA Model Contract contains detailed contract language for proposing new contracts and renegotiating to improve existing contracts. It contains language that is highly specific for provision of home infusion therapy services and was developed to help providers:
Commercial Payor Recommendations
NHIA has developed recommendations designed to be incorporated into contracts between health plans and home and alternate site infusion providers. NHIA encourages providers to download this resource and use it in contracting discussions.
