Begin with the exact intended purpose in the label, instructions for use, promotional or sales materials, and clinical evaluation. Article 2 defines intended purpose by those manufacturer-supplied materials, and MDCG 2021-24 warns that it is the manufacturer's intended purpose, not accidental use or the class of similar products, that determines the class.
Record the clinical purpose, patient or user group, body contact, duration of use, invasiveness, active function, measuring function, medicinal or biological interaction, software output, and whether the device is used alone, in combination, as a system, or as a procedure pack.