42 CFR § 456.143 - Content of medical care evaluation studies.
Each medical care evaluation study must -
(b) Include analysis of at least the following:
(2) Durations of stay;
(3) Ancillary services furnished, including drugs and biologicals;
(4) Professional services performed in the hospital; and
(c) If indicated, contain recommendations for changes beneficial to patients, staff, the hospital, and the community.