Accuracy of Digital Tympanic, Oral, Axillary, and Rectal Thermometers Compared with Standard Rectal Mercury Thermometers

OBJECTIVE: To compare a number of electronic tympanic, oral, axillary, and rectal measurements with those taken with a standard rectal mercury thermometer. DESIGN: Prospective open study. SETTING: County hospital, Denmark. SUBJECTS: 200 patients. INTERVENTIONS: Each of 200 patients had 6 electronic measurements of body temperature: 3 in the auditory canal using Ivac Core Check 2090A, Diateck 9000, and Genius 3000A, 1 in the axilla using Terumo Digital C202. 1 in the mouth using Terumo Digital C402, and 1 in the rectum using a Terumo Digital C402. These were compared with readings from a standard mercury glass thermometer in the rectum. MAIN OUTCOME MEASURES: Accuracy of electronic thermometry. RESULTS: The rectal electronic measurements were closest to the rectal mercury readings, with a mean (SD) of -0.05 degrees C (0.12), whereas the other measurements gave unacceptable SDs of temperature differences ranging from 0.41 degrees C to 0.53 degrees C. CONCLUSIONS: We conclude that electronic rectal temperature measurements are the most accurate. We do not recommend electronic tympanic, oral, or axillary measurements.