Which abbreviation corresponds to Rectal (rectum)?

• A. o
• B. ax
• C. ty
• D. r

Answer: (D)

Abbreviations for where a measurement comes from are used to show the method quickly. For temperature, each route has its own shorthand. The single-letter abbreviation r is used to denote rectal (rectum). This distinguishes it from other common routes: o for oral, ax for axillary, and ty for tympanic. Rectal readings are typically about 0.5 to 1°F higher than oral readings, and are used when the most accurate measurement is needed or with certain patients (like infants or when the patient cannot cooperate with other routes). So the abbreviation that best represents rectal is r.