Measuring function

Under the EU MDR, a class I device with a measuring function needs a notified body for the aspects related to metrology, so the answer has practical consequences. All the MDCG 2021-24 criteria must be met together, and the expected accuracy is often what decides borderline cases.

The following criteria, if fulfilled together, indicate that a device has a measuring function: a) The device is intended by the manufacturer to measure: - quantitatively a physiological or anatomical parameter, or - a quantity or a quantifiable characteristic of energy or of substances (including medicinal products) delivered to or removed from the human body. Spoons or plastic syringes co-packed with medicinal products and used to measure a quantity of that medicinal product to be administered to the patient are in this category. Devices for the delivery of liquid to the human body without graduation or scale (e.g. medicine spoons, cups, droppers without graduation or scale or display of measuring unit) are not in this category. b) The result of the measurement: - is displayed in legal units or other acceptable units within the meaning of Directive 80/181/ECC, or - is compared to at least one point of reference indicated in legal units or other acceptable units in compliance with the mentioned directive.. c) The intended purpose implies accuracy, claimed explicitly or implicitly, where a non-compliance with the implied accuracy could result in a significant adverse effect on the patient’s health and safety. The expression ‘claimed implicitly’ covers cases where the user, on the basis of the designation of the device or of its accompanying documents, or on the basis of the common use, is entitled to expect accuracy where the accuracy of the measurement has an impact on the diagnosis or therapy of the patient. Measuring activities during the manufacturing process including those for calibration purposes are not covered and do not imply a measuring function of the manufactured device.

MDCG 2021-24 Rev.1, Section 3.1, Basic terms and definitions (Devices with a measuring function)