In terms of observation, what does not qualify as a medical sign?

A medical sign is an objective indication of a medical condition that can be observed or measured by a healthcare professional. In contrast, patient-reported pain is a subjective experience; it is based on the individual's personal sensation, perception, and response to discomfort. This means that while healthcare providers can evaluate the severity of pain through various scales, the pain perception itself cannot be quantified or observed by them in the same direct manner as physical signs.

On the other hand, a skin rash, swelling, and blood pressure readings are all observable and measurable by a clinician. A skin rash is an external visual sign that can be examined, swelling can be assessed through palpation or visual observation, and blood pressure readings are taken using medical instruments to provide quantifiable data about a patient's vascular health. Each of these reflects a condition that can be clearly identified and documented, which aligns them with the definition of a medical sign.