Evaluating the Performance of Laboratories Testing Sphygmomanometers in Legal Metrology due to Proficiency Testing

Proficiency testing is a vital component to ensure quality of tests and calibrations. In particular in legal metrology, the scope of activities claiming for accreditation demands for specific proficiency testing. This study presents the results of the proficiency testing conducted in 2019, in Brazil, for sphygmomanometers, an instrument usually under legal metrology regulation, whose measurements have a direct impact on clinical diagnosis and treatments, according to the International Organization of Legal Metrology Recommendation. The tests comprised initial verification, encompassing general inspection, rapid exhaust valve and maximum permissible error for the cuff indication tests, using the Z - Score as the criteria for the performance of the participants. Five ISO/IEC 17025-accredited laboratories, in Brazil, participated in the proficiency testing. The results show that all five laboratories obtained satisfactory results for the rapid exhaust valve test. One laboratory obtained a questionable result in one measurement for the maximum permissible error test. All laboratories obtained unsatisfactory results for the general inspection. Since the legal metrology requirement comprises all three tests, all laboratories obtained unsatisfactory performance. The results unveiled the necessity for corrective actions to improve the legal control of sphygmomanometers in Brazil. This proficiency testing was also included on the European PT Information System (Eptis) platform.