The Braun ThermoScan measures the infrared heat generated by the eardrum and surrounding tissue. Since the eardrum shares blood supply with the temperature control centre in the brain, the ear accurately reflects changes in the core body temperature.
Braun ThermoScan has been proven to be as accurate as rectal measurement, including on newborns. The probe of the thermometer can safely be used to measure the temperature with new-borns as it does not have to be fully inserted into the ear canal to get an accurate measurement.