Which abbreviation commonly appears in medical notes?

The abbreviation that commonly appears in medical notes is recognized as BP, which stands for blood pressure. This term is frequently used in clinical settings to denote a vital sign that measures the force of blood against the walls of arteries. Blood pressure readings are a critical part of patient assessments and are routinely documented in medical notes to monitor a patient’s cardiovascular health.

The other choices do exist within medical terminology but are less frequently documented in a standard way. For example, while HR could refer to heart rate and is used in assessments, it isn't as standard in documentation just as blood pressure is. MD typically stands for doctor of medicine and is not regularly noted in the patient’s medical records in the same way blood pressure is. Similarly, RX is commonly associated with prescriptions but is not typically found in routine patient assessment notes. Blood pressure, on the other hand, is a key clinical measurement and therefore consistently appears in medical documentation.