Which site provides the most accurate temperature reading for a newborn?

• A. Skin
• B. Tympanic
• C. Rectal
• D. Axillary

Answer: (A)

Measuring a newborn’s temperature aims to reflect the body's true core temperature rather than surface warmth. The reading taken rectally is the most accurate single-site measure because it most closely mirrors core temperature and is less affected by peripheral blood flow or environmental factors. This makes it the preferred method when a precise assessment is needed, though it must be done with care to avoid injury. Other sites are safer and easier but less reliable: axillary measurements can underestimate core temperature and are influenced by ambient conditions; tympanic readings in newborns can be unreliable due to tiny ear canals and variability in technique and external factors; and skin temperature is highly affected by room temperature and peripheral perfusion, so it does not accurately reflect core temperature. So, for the most accurate reading, rectal measurement is best, with awareness of its safety considerations.