The antitrust rules only apply to activities affecting interstate commerce.

A. In Summit Health, Ltd. v. Pinhas, --U.S.--, 111 S.Ct. 1842 (1991), the Supreme Court ruled that a hospital's revocation of one physician's medical staff privileges affected interstate commerce sufficiently to invoke the jurisdiction of the Sherman Act. The court presented a standard that the competitive significance of the activity must be measured by a general evaluation of the impact of the restraint on other participants in the market from which the individual was a member. If there is an impact in that market, and that market affects interstate commerce, then Sherman Act jurisdiction is conferred. This case appears to effectively precluded any hospital defense to an antitrust suit based on lack of affect on interstate commerce.