A clinical sign is an observable indication of a medical condition that can be detected by a healthcare professional during an examination. These signs can include physical symptoms like a rash, swelling, or abnormal heart sounds. They help doctors diagnose illnesses and monitor a patient's health status. Clinical signs are different from symptoms, which are reported by the patient, such as pain or fatigue. For example, a doctor might notice a fever as a clinical sign, while the patient might describe feeling chills. Together, these observations guide treatment decisions and improve patient care.