This study presents a methodology for the design and validation of a test protocol aimed at evaluating the reliability and safety of external defibrillators used in hospital environments. The protocol was developed based on international standards, manufacturer specifications, and professional criteria from the field of clinical engineering. A risk assessment identified 15 initial attributes that allowed prioritization of critical control points. The design also addressed technical, operational, and managerial requirements necessary to ensure the feasibility of the testing service, including infrastructure, qualified personnel, and instrumentation. Validation was performed on a representative sample of 38 devices from different brands and models, demonstrating the robustness and reproducibility of the final protocol. The application of the developed protocol is expected to contribute to the detection of potential failures, quality and performance assessment and life cycle management of hospital medical devices. The proposed methodology for test protocol design emerges as an effective tool for the development of testing plans for all medical technologies, supporting evidence-based decision-making in clinical engineering and reinforcing patient safety.