Final answer:
During a review of systems, a nurse gathers primarily subjective information based on the patient's personal symptoms, which cannot be directly measured. Objective data can also be collected through physical assessments to corroborate subjective complaints.
Step-by-step explanation:
When a nurse is performing a review of systems (ROS) on a patient, they are collecting primarily subjective information. This is information that expresses the patient's personal experience with their symptoms such as pain, nausea and fatigue which cannot be directly measured or observed by the nurse. It is based on the patient's self-report and personal experience of their health status.
Objective information on the other hand, consists of measurable observable data that the nurse can confirm through physical examination such as blood pressure readings heart rate and lab test results. However, nurses also collect some objective information during a review of systems when validating the subjective complaints with physical assessments.