Which abbreviation would indicate that a patient must not eat or drink prior to a procedure?

The abbreviation NPO stands for the Latin phrase "nil per os," which translates to "nothing by mouth." This directive is typically used in medical settings to indicate that a patient should refrain from eating or drinking prior to a procedure. It is crucial for various reasons, including minimizing the risk of aspiration during anesthesia or certain diagnostic tests. Understanding this abbreviation is essential for ensuring the safety and proper care of patients before they undergo procedures.

The other options represent different medical terminologies. IM refers to intramuscular, indicating a method of delivering medication, OU signifies both eyes in ocular treatments, and Tx commonly denotes treatment. These terms provide important information but do not relate to dietary restrictions prior to a procedure.