Stark In-Office Ancillary Services Exception (42 CFR 411.355(b))
Ownership/investment and compensation exception permitting many group-practice ancillary services (lab, imaging, PT) when furnished in the same building or centralized building under defined conditions.
Primary source
42 CFR 411.355(b) — eCFR →https://www.ecfr.gov/current/title-42/chapter-IV/subchapter-B/part-411/subpart-J/section-411.355#p-411.355(b)
Verified May 23, 2026 · This is the authoritative regulator URL. The summary below is a research aid; the linked source controls.
42 CFR 411.355(b)) is the in-office ancillary services (IOAS) exception. It is the structural reason group practices can offer in-house lab, imaging, PT, and other ancillaries without each referral being a Stark violation.
Three categories of conditions:
Performance — services must be furnished by (1) the referring physician personally, (2) a physician who is a member of the same group practice, or (3) an individual supervised by such physician.
Location — services must be furnished in (1) the same building where the referring physician (or another member of the group) regularly furnishes physician services unrelated to DHS, or (2) a "centralized building" used by the group practice exclusively for some or all of its DHS.
Billing — services must be billed by the performing physician, by the group, by a wholly-owned subsidiary of the group, or by a third party in the group's name and TIN.
The exception is unavailable for certain DHS categories (most DME, parenteral nutrients, home health). The "group practice" definition at 42 CFR 411.352 is itself substantive: unified business, single legal entity, members furnish substantially the full range of services, productivity bonuses with specific tests, and compliant compensation methodologies.
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Related across the archive
- RegulationStark Group Practice Definition (42 CFR 411.352)Strict structural and operational definition of 'group practice' for purposes of the in-office ancillary services exception and physician services exception.
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Last reviewed May 23, 2026 · Citation verified May 23, 2026
Research aid, not legal advice. This summary is an administrative research aid prepared by D3rx. It does not certify compliance, provide legal advice, replace counsel, or guarantee an audit outcome. For authoritative regulatory text follow the primary source link at the top of this page. The practice remains responsible for reviewing, adopting, and maintaining its compliance program.