Definition of Ambulatory Surgical Center (ASC)

An ASC for purposes of this benefit is a distinct entity that operates exclusively for the purpose of furnishing outpatient surgical services to patients. It enters into an agreement with CMS to do so. An ASC is either independent (i.e., not a part of a provider of services or any other facility), or operated by a hospital (i.e., under the common ownership, licensure, or control of a hospital). To be covered as an ASC operated by a hospital, a facility elects to do so, and continues to be so covered unless CMS determines there is good cause to do otherwise. This provision is intended to prohibit such an entity from switching from one payment method to another to maximize its revenues . For other general conditions and requirements,  If the hospital based surgery center is certified as an ASC it is considered an ASC and is subject to rules for ASCs. Related survey requirements are published in the State Operations Manual, Pub. 100-07, Appendix L. Claims processing and payment requirements for ASCs are published in Pub. 100-04, the Medicare Claims Processing Manual, chapter 14.

If a hospital based surgery center is not certified as an ASC it continues under the program as part of the hospital. In that case the applicable hospital outpatient payment rules apply. This is the outpatient prospective payment system (OPPS), for most hospitals, or may be provisions for hospitals excluded from OPPS. See Pub.100-04, the Medicare Claims Processing Manual, chapter 4, for billing and payment requirements for hospital outpatient services.

Indian Health Service (IHS) hospital outpatient departments are not certified as separate ASC entities. The ASC indication merely means that CMS approved them to bill for ASC services and be paid based on the ASC rates for services on the ASC list. In order to bill for ASC services, the hospital outpatient department must meet the conditions of participation for hospitals defined at 42 CFR, Part 482.