Assessment of the accuracy and reliability of clinical thermometers for body temperature measurements at the hospital: a laboratory study

Abstract

This study aims to assess the accuracy and reliability of two different types of thermometers: contact thermometers and non-contact thermometers at Maharaj Nakorn Chiang Mai Hospital. The comparison method was carried out in a hospital laboratory setting and followed a specific calibration procedure. The mean readings, errors, and measurement uncertainties were reported and categorized according to the manufacturer's labeling models. The maximum permissible errors (MPE) were defined by international standards and clinical acceptances for contact and non-contact thermometers, respectively. The results showed that thermometers of temperature probes (PTs) provided the highest level of accuracy. When compared to a reference standard thermometer (STD), the mean errors were only 0.04 ºC at the calibration point of 37.0 ºC. For digital contact thermometers (CTs), the mean error at the calibration points of 37.0 ºC was 0.24 ºC. Most CT models exhibited high accuracy and reliability. However, the forehead (IRFTs) and ear (IRETs) readings significantly differed from the STD, with over half of all units not meeting the ISO 80601-2-56/ASTM E1965-98 standard requirements. These results suggest that CTs and PTs are highly accurate and reliable devices for measuring body temperature. However, both IRFTs and IRETs could be useful in certain situations, such as screening many people in a short amount of time, but their accuracy should be interpreted with caution and confirmed using a more precise method if necessary.