[303756] Artigo – CBM – Congresso Brasileiro de Metrologia

Resumo: The clinical electrical thermometer (CET) is a measuring instrument in the health area, with metrological technical regulation approved by Inmetro Ordinance No. 325 of July 28, 2021 (MTR No. 325/21). According to this regulation, there are two types of CET’s, depending on the algorithm of the manufactured model: non-predicting (thermal equilibrium) and predicting (calculating), with three possible application sites on the body: axilla, mouth (sublingual) and rectum. The type approval applicants of almost all models submitted for type evaluation were declared non-predicting. Still, while evaluating some of these models, the clinical tests submitted corresponded with the predictive method. Additionally, the aggravating factor is that the results of these clinical tests did not comply with the regulation, as the indication varied by more than 0.2°C between the moment of the alarms and after 5 minutes in most measurements.

Nonetheless, since are analyzed the clinical tests in a preliminary phase, allowing for document correction, the applicants submitted other clinical tests in the required format for non-predicting. For this measuring method, variations in CET indication are not required after finishing measurement alarms by the regulation, assuming they do not occur due to the thermometer being non-predicting. Consequently, the evaluation process could proceed normally, even with technical doubts about the actual measurement method and the understanding that the operation was inconsistent with the declared method. For a better understanding, we reviewed the literature on the physics of thermometers and human body physiology, a documentary analysis of previously approved models, and the requirements of MTR No. 325/21 to seek possible explanations for these occurrences. As a result, the need for improvements in this regulation was identified, and some changes in the type of evaluation procedures have already been implemented.