IVDs and risk class: from the Directive to the Regulation

The risk classification system of the IVDR is rule based

The Directive on IVD medical devices (98/79/EC) sets up specific categories of devices in order to determine the appropriate conformity assessment route. There is no clear indication of a hierarchy of risk although it is implied by the conformity assessment requirements to which each of these categories is subject to. This implied risk hierarchy is as follows, beginning with the highest risk category and ending with the lowest:

• Annex II List A related to determination of blood groups and the identification of markers for various blood borne pathogens — human immunodeficiency virus (HIV), human T-cell leukaemialymphoma virus (HTLV) and hepatitis as well as the detection of variant Creutzfeldt–Jakob Disease (vCJD)
• Annex II List B related to the detection of certain diseases
• Devices for self-testing (other than those listed in Annex II List A and B)
• All other IVD devices

The risk classification system of the IVDR is rule based, although it retains a residue of the old system of the Directive by resorting to a certain degree of listing, in particular with respect to blood-borne markers (e.g. ABO blood typing).

The IVDR establishes four risk classes D, C, B, and A, with D being the highest risk class and A the lowest. There are altogether seven classification rules (Annex VIII). The Commission may issue implementing acts that would change the existing rules (Art. 47.3-4).

Broadly speaking the four classes cover IVD devices as follows:

• Class D covers general life-threatening conditions and more specifically transmissible agents in blood and biological materials intended to be transplanted or re-administered into the body. Such transmissible agents may also present a high risk to the wider population. It also specifically covers blood grouping or tissue typing when this involves markers of the following systems: ABO, Rhesus, Kell, Kidd and Duffy
• Class C covers a diverse mix of high-risk IVD devices which present a lesser risk to the wider population. It tends to include situations where the failure of a diagnosis could be life-threatening, including testing for infectious diseases and cancer. It also covers fields such as companion diagnostics and genetic screening. In addition, Class C covers self-testing IVD devices in general (see exceptions below)
• Class B is the default class that takes in all IVD devices that are not covered specifically in other classification rules. This is a departure from the system applied to other medical devices for which the default class is Class I, i.e. the lowest risk class. It tends to cover devices that present lower risks to the patient and the population at large than IVD devices in Classes D and C. Class B also covers self-testing IVD devices for pregnancy and fertility testing as well as detection of cholesterol levels and detection of glucose, erythrocytes, leucocytes and bacteria in urine. Controls without a quantitative or qualitative assigned value are also in Class B
• Class A covers broadly speaking laboratory devices (e.g. wash buffers), instruments and specimen receptacles

The major consequence of the new classification system is that in contrast with the current system most IVD devices will be subject to verification and certification by notified bodies. Only Class A devices are allowed on the market based on self-certification.

Regulatory requirements will be more demanding under the IVDR for all IVD devices in any case, but the need to prove compliance to a notified body prior to CE marking will increase the burden on the manufacturers and result in a higher cost of regulatory compliance. In some cases, it may not be possible to generate adequate proof of compliance with the new requirements. These factors may result in some devices no longer being commercially viable.

This is an excerpt from the BSI medical devices white paper: Explaining IVD classification issues. To browse our collection of medical device white papers, please visit the Insight page on the Compliance Navigator website.