A review of systems (ROS), also called a systems enquiry or systems review, is a technique used by healthcare providers for eliciting a medical history from a patient. It is often structured as a component of an admission note covering the organ systems, with a focus upon the subjective symptoms perceived by the patient (as opposed to the objective signs perceived by the clinician). Along with the physical examination, it can be particularly useful in identifying conditions that do not have precise diagnostic tests.[1]