Review of the medical necessity of hospital or other health facility admissions upon or within a short period following an admission and the periodic review of services provided during the course of treatment. The initial review usually assigns an appropriate length of stay to the admission (using diagnosis specific criteria) which may also be reassessed periodically. Where concurrent review is required, payment for unneeded hospitalizations or services is usually denied. HEW recently issued utilization review rules which would have required concurrent review (defined as review within one working day of admission) of all Medicare and Medicaid cases after July 1, 1975. Admissions which were found unnecessary would not have been reimbursed under either Medicare or Medicaid beyond three days after this finding. As a result of suit by the AMA against implementation of certain portions of these regulations, particularly the concurrent review requirement, implementation of the requirements was enjoined by temporary injunction. HEW is rewriting the regulations. Under the enjoined regulations, review was to be conducted by a physician member or by a qualified non-physician member of the committee or group assigned the utilization review responsibility in each hospital. Such individual was to be appropriately trained and qualified to perform the assigned review functions, and the review was to use criteria selected or developed by the hospital utilization review committee or group. Concurrent review should be contrasted with a retrospective medical audit, which is done for quality purposes and does not related to payment, and claims review, which occurs after the hospitalization is over.