UK IVD Classification: List A, List B and Self-Testing

1. Key takeaways

The classification of IVDs in the United Kingdom still uses the list-based structure of Annex II of Directive 98/79/EC: List A (the highest risk, such as blood-screening reagents for HIV and hepatitis B), List B (next in risk, such as blood grouping and certain infectious disease tests), devices for self-testing, and everything else as general IVDs. This is structurally different from the four risk classes A, B, C and D of the EU IVDR, and it is the single easiest point to get wrong for teams arriving with an IVDR mindset: the reflexive habit of assigning a class letter must be replaced by a list-matching exercise. Until the proposed reform takes effect, the list determines both the conformity assessment route and the registration position, so a correct list determination is the foundation on which every other IVD obligation in Great Britain is built.

2. Legal basis

The Part IV provisions and the directive annex they invoke cover the full IVD lifecycle:

• UK MDR 2002 (SI 2002/618, as amended): Part IV, regulations 32–44ZB; regulation 33 (scope), regulation 34 (essential requirements), regulation 36 (UK marking for IVDs), regulation 40 (affixing procedures), regulation 41 (manufacturers and conformity assessment procedures), regulation 42 (approved bodies), regulation 43 (devices for performance evaluation), regulations 33A and 44 (registration of IVDs), regulation 44ZA (duties performed under Directive 98/79), regulation 44ZB (duties performed under Regulation (EU) 2017/746).
• Directive 98/79/EC: Annex II (List A and List B).
• SI 2023/627, regulation 9: amendment of regulation 44ZA, including the approved body involvement determination in regulation 44ZA(3A).

The two bridging provisions deserve special attention: regulation 44ZA carries forward obligations satisfied under the IVDD, while regulation 44ZB recognises obligations satisfied under the EU IVDR. Which of the two applies to a given product depends on the European certificate it holds, and that determination must be made and recorded for every SKU.

3. Expert insights

Insight 1: list classification works by matching, not by reasoning through rules. Unlike the rule-based system for devices, List A and List B are enumerated lists — a product that matches an entry falls into that tier, with no rule-by-rule analysis required. Two consequences follow. First, the determination is comparatively rigid. Second, a new product that does not appear on any list falls automatically into the general IVD category, which may place it at a significantly lower risk tier than the same product would occupy under the EU IVDR. Teams accustomed to gradient reasoning must consciously invert their method: the question is not how risky the product is, but whether it matches an enumerated entry.

Insight 2: IVDR certificates are recognised in Great Britain through regulation 44ZB. An IVD holding a CE certificate under the EU IVDR may perform its Part IV duties under regulation 44ZB; a device relying on the IVDD uses regulation 44ZA. SI 2023/627, regulation 9(2), replaced the wording amended from time to time in regulation 44ZA(1)(a) with it had effect on 25 May 2022 — that is, the reference point of the IVDD has been frozen. Certificates and assessment positions should therefore be checked against the directive text as it stood on that date, not against any later revision, and the frozen date should appear in the compliance records.

Insight 3: the classification reform is already on its way. The official consultation response proposes moving United Kingdom IVDs from the list structure to the IMDRF-aligned four classes A, B, C and D, within a proposed pre-market statutory instrument. That instrument had not yet entered into force as of the search date, and the current rules remain List A and List B. Companies should monitor the legislative progress without pre-applying the future classes, since acting on a proposal that has not been made law creates divergence from the obligations that actually apply today.

4. Practical recommendations

GRZAN recommends that IVD manufacturers maintain two classification mapping tables in parallel: one for the current United Kingdom structure — List A, List B, self-testing and general IVDs — and one for the EU IVDR classes A to D, with the correspondence between the two recorded for every product. When the proposed reform is enacted, the mapping can be migrated directly instead of re-inventorying the full SKU portfolio under time pressure. In addition, devices used for performance evaluation must be clearly flagged as such at registration (regulation 44), and the subsequent move to formal placing on the market requires a fresh registration — the status field is not cosmetic, and leaving it stale creates inconsistencies in the registration database.

5. Verification checklist

• □ List A / List B / self-testing / general IVD status has been determined under Annex II of Directive 98/79/EC
• □ A mapping table between the United Kingdom and EU IVDR classifications has been established
• □ The governing European legal basis (IVDD or IVDR, corresponding to regulation 44ZA / 44ZB) has been confirmed
• □ Devices for performance evaluation have been flagged in accordance with regulation 44
• □ Legislative progress on the IVD classification reform is being monitored

Legal information verified as of 29 October 2026.

GRZAN supports manufacturers with the following services for the United Kingdom market:

• Appointment of the UK Responsible Person (UKRP) and signature support for the letter of authorisation
• End-to-end MHRA registration (DORS) filing and account lifecycle management
• Device classification determination, GMDN code selection and annual registration fee estimation
• Dual-track design for Great Britain and Northern Ireland, including UK(NI) solutions
• Post-market surveillance (PMS) system setup, PMSR/PSUR preparation and vigilance report submission
• Emergency response to serious incidents and field safety corrective actions (FSCA)
• Monitoring of UK regulatory changes and compliance gap assessment

GRZAN provides end-to-end MHRA registration and compliance support for manufacturers entering the United Kingdom market, covering every stage from market entry planning through post-market obligations. For enquiries, contact info@grzanglobal.com.