Why do temperature readings vary when obtained from different body sites with digital thermometers?
Click here to see our selection of digital thermometers. A: There are four sites where body temperature is usually measured: ear, mouth, rectum, and skin (underarm). Variations in temperature readings from one site to the other are often a result of: 1. Distance from vital organs such as the heart and brain, which represent the body’s core temperature. 2. Increase in temperature as a result of biochemical activity, usually reflected in rectal measurements. 3. Variations in temperature while breathing, eating, and drinking while measuring temperature orally. 4. Variations in temperature due to perspiration, external temperature, and medication, are usually reflected in skin temperature measurements.