A diagnostic tool is a device or software used to identify and analyze problems within a system, often in fields like medicine, engineering, or information technology. These tools help professionals gather data, assess conditions, and determine the root causes of issues, enabling effective solutions. In healthcare, for example, a diagnostic tool can be a medical imaging device like an MRI or a blood test that helps doctors understand a patient's health status. In IT, diagnostic tools can include software applications that troubleshoot computer issues, ensuring systems run smoothly and efficiently.