Dutch hospitals are required to screen older patients for functional decline using 4 indicators: malnutrition, delirium, physical impairment, and falls, to recognize frail older patients promptly. The Functional Resonance Analysis Method was employed to deepen the understanding of work according to the protocols (work-as-imagined [WAI]) in contrast to the realities of daily practice (work-as-done [WAD]). Data have been collected from 3 hospitals (2 tertiary and 1 general) and 4 different wards: an internal medicine ward, surgical ward, neurology ward, and a trauma geriatric ward. WAI models were based on national guidelines and hospital protocols. Data on WAD were collected through semistructured interviews with involved nurses (n = 30). Hospital protocols were more extensive than national guidelines for all screening indicators. Additional activities mainly comprised specific preventive interventions or follow-up assessments after adequate measurements. Key barriers identified to work according to protocols included time constraints, ambiguity regarding task ownership, nurses' perceived limitations in applying their clinical expertise due to time constraints, insufficient understanding of freedom-restricted interventions, and the inadequacy of the Delirium Observation Scale Score in patients with neurological and cognitive problems. Performance variability stemmed from timing issues, frequently attributable to time constraints. The most common reasons for deviating from the protocol are related to time constraints, lack of knowledge, and/or patient-related factors. Also, collaboration among relevant disciplines appears important to ensure good health outcomes. Future research endeavors could shed a light on the follow-up procedures of the screening process and roles of other disciplines, such as physiotherapists.