ISO 80601-2-56:2017 applies to the basic safety and essential performance of a clinical thermometer in combination with its accessories, referred to as ME equipment. ISO 80601-2-56:2017 specifies the general and technical requirements for electrical clinical thermometers. ISO 80601-2-56:2017 applies to all electrical clinical thermometers that are used for measuring the body temperature of patients. Clinical thermometers can be equipped with interfaces to accommodate secondary indicators, printing equipment, and other auxiliary equipment to create ME systems. ISO 80601-2-56:2017 does not apply to auxiliary equipment. ME equipment that measures a temperature not as a primary purpose, but as a secondary function, is outside the scope of ISO 80601-2-56:2017.