A form of medical care review in which an assessment is made of the medical necessity of a patients admission to a hospital or other inpatient institution. Admission certification seeks to assure that patients requiring a hospital level of care, and only such patients, and admitted to the hospital without unnecessary delay and with proper planning of the hospital stay. Lengths of stay appropriate for the patient’s admitting diagnosis are usually assigned and certified, and payment by any program requiring certification for the assigned stay is assured. Certification can be done before (preadmission) or shortly after (concurrent) admission.