Armpit temperatures are usually the least accurate. For older children and adults oral readings are usually accurate as long as the mouth is closed while the thermometer is in place. It captures the naturally emitted heat from the skin over the temporal artery taking 1000 readings per second and selects the highest reading. Oral and axillary temperature readings are about ½ to 1f 3c to 6c below rectal. It is important to remember. Rectal temperatures provide the best readings for infants especially those 3 months or younger as well as children up to age 3.
It is passed over the temporal artery in the forehead. 1 core body temperature is regulated by both peripheral and central receptors that are integrated within the hypothalamus. Fever in most adults a fever is an oral temperature above 1004f 38c or a rectal or ear temperature above 101f 383c. 2 autonomic as well as behavioral responses to changes in temperature maintain homeostasis or a range of normal around 37 c. Add these numbers to oral and axillary temperature readings for the most accurate reading. The pulmonary artery catheter which measures blood temperature is considered the gold standard for measuring core temperatures.
A forehead temporal scanner is usually 05f 03c to 1f 06c lower than an oral temperature. Rectal temperatures are considered most accurate indication of the bodys temperature. The most accurate way to measure temperature is to take a rectal reading. Rectal temperatures are generally thought to be the most accurate for checking a young childs temperature. It provides an accurate arterial temperature. The temporal artery thermometer is the most accurate noninvasive way to measure body temperature.