Device Classification under MDR Annex VIII and IVDR Annex VIII
Classification drives everything downstream: the conformity assessment route, the depth of technical documentation review, PSUR frequency and UDI deadlines. The exam tests whether you can apply Annex VIII rather than recite a list of rules.
MDR: structure of Annex VIII
Chapter I defines duration of use (transient under 60 minutes, short-term from 60 minutes to 30 days, long-term over 30 days), invasive and surgically invasive devices, active devices and implantables. Chapter II gives implementing rules: accessories are classified separately; if several rules apply, the highest class wins; classification follows the intended purpose; software is classified independently of the hardware it runs on. Chapter III holds the 22 rules.
High-yield rules: Rule 11 puts most software informing diagnostic or therapeutic decisions in Class IIa, rising to Class III where a decision may cause death or irreversible deterioration, and puts monitoring software for vital parameters where variation creates immediate danger in Class IIb. Rule 8 places implantables in Class IIb, and Class III where in direct contact with the heart, central circulatory system or central nervous system. Rule 13 places devices incorporating an ancillary medicinal substance in Class III. Rule 21 covers substances absorbed after introduction through a body orifice or application to skin.
IVDR: seven rules, four classes
The IVDR uses Classes A to D, combining individual risk with public-health risk. Rule 1 defaults to A; Rule 2 places blood grouping and tissue typing in D; Rule 3 places detection of transmissible agents relevant to donation and life-threatening agents in D; Rules 4 and 5 raise self-testing and near-patient testing; Rule 6 captures professional-use devices not otherwise covered.
Worked example
An app analyses home-measured blood pressure and alerts the patient, with no clinician decision. Under Rule 11 the decision limb does not apply, because no diagnostic or therapeutic decision is informed. The monitoring limb applies because a variation in a vital parameter creates immediate danger, so the device is Class IIb. If the app also proposed a dose adjustment, the decision limb would apply: Class IIa, moving to Class III where death or irreversible deterioration is possible.
Traps
Choosing the highest class without documenting the rules considered; classifying by technology rather than intended purpose; assuming a sterile Class I device stops being Class I (it still needs a notified body for the sterile aspects); and overlooking implementing rules that reclassify accessories or software.