[Oral contra rectal measurement of body temperature]

The electronic thermometers for oral use employed in Middelfart Hospital (Ivac, TN III and Crafttemp) were compared with mercury thermometers for rectal use. Employment of all the thermometers in question in a water bath revealed considerable accuracy where the mercury thermometers were concerned but considerable divergence and deviations where the electronic thermometers were concerned and this was particularly marked with increasing temperature. Pyrexia is defined as temperature greater than or equal to 37.0 degrees C orally and greater than or equal to 37.5 degrees C rectally. In the clinical investigation of the ability of establishing the diagnosis of pyrexia in 147 patients a true negative diagnostic frequency (diagnostic sensitivity) for the electronic thermometers was found to be 0.94 as compared with the mercury thermometers employed rectally which is considered to be satisfactory as a screening method but, with the limits chosen, a true positive diagnostic frequency (diagnostic specificity) of 0.37 was found. No significant differences in the median temperature were found as regard age greater than or equal to 70 years or prostheses in the lower jaw. It is recommended that a raised temperature on oral measurement with the thermometers mentioned above should be controlled with rectal measurement with a mercury thermometer.