You have an assay that works, a performance evaluation plan in draft and a notified body shortlist. Then someone asks: what class is it? Under the IVDR the answer sets whether a notified body is involved at all, which conformity assessment annex applies and which transition date you are working towards.
The IVDR classification rules in Annex VIII of Regulation (EU) 2017/746 are only seven rules long, but they are easy to misread. This guide covers the implementing rules, each classification rule, the MDCG 2020-16 interpretation and worked examples taken from the rule text and that guidance.
How IVDR classification works: Article 47 and Annex VIII
Article 47(1) IVDR divides devices into four classes — A, B, C and D — taking into account their intended purpose and inherent risks, with classification carried out in accordance with Annex VIII.
The class matters because Article 48 attaches a conformity assessment route to each one:
- Class D (Article 48(3)–(6)): notified body assessment, plus EU reference laboratory verification where one is designated.
- Class C (Article 48(7)–(8)): notified body assessment, with technical documentation reviewed for at least one representative device per generic device group.
- Class B (Article 48(9)): notified body assessment, with technical documentation reviewed for at least one representative device per category.
- Class A (Article 48(10)): self-declaration, except sterile Class A devices, where the notified body’s role is limited to sterility aspects.
Self-testing and near-patient devices in Classes B and C also go through the technical documentation assessment in Section 5.1 of Annex IX. If you disagree with your notified body about the class, Article 47(2) sends the question to the competent authority of the Member State where the manufacturer, or its authorised representative, has its registered place of business.
The implementing rules you must apply first
Section 1 of Annex VIII sets ten implementing rules. The ones that change outcomes most often are:
- 1.1 — classification is governed by the intended purpose of the device.
- 1.3 — accessories are classified in their own right, separately from the device they are used with.
- 1.4 — software that drives or influences the use of a device falls in the same class as that device; software independent of any other device is classified in its own right.
- 1.5 and 1.6 — calibrators, and control materials with quantitative or qualitative assigned values, take the class of the device they are intended for.
- 1.8 — if a device has several intended purposes that fall into different classes, it takes the highest of them.
- 1.9 — if several rules apply, the rule resulting in the higher classification applies.
- 1.10 — the rules apply equally to first-line, confirmatory and supplemental assays.
Rules 1.8 and 1.9 mean classification is never “first match wins”: test every rule and keep the highest class.
The seven IVDR classification rules in Annex VIII
Rule 1 — Class D
Devices intended to detect a transmissible agent, or exposure to it, in blood, blood components, cells, tissues, organs or their derivatives to assess suitability for transfusion, transplantation or cell administration; to detect a transmissible agent causing a life-threatening disease with a high or suspected high risk of propagation; or to determine the infectious load of a life-threatening disease where monitoring is critical to patient management.
Rule 2 — Class C, or Class D for named blood group markers
Blood grouping and tissue typing devices intended to ensure immunological compatibility for transfusion, transplantation or cell administration are Class C. They are Class D when they determine the markers listed in the rule: ABO (A, B, AB), Rhesus (RH1 (D), RHW1, RH2 (C), RH3 (E), RH4 (c), RH5 (e)), Kell (Kel1 (K)), Kidd (JK1, JK2) and Duffy (FY1, FY2).
Rule 3 — Class C
Rule 3 lists thirteen purposes, points (a) to (m). They include sexually transmitted agents; infectious agents in cerebrospinal fluid or blood without a high risk of propagation; companion diagnostics (point (f)); cancer screening, diagnosis or staging (point (h)); human genetic testing (point (i)); monitoring levels of medicinal products, substances or biological components where an erroneous result could lead to a life-threatening patient management decision (point (j)); management of patients with a life-threatening disease or condition (point (k)); and screening for congenital disorders in the embryo, foetus or new-born babies (points (l) and (m)).
Rule 4 — self-testing and near-patient testing
Self-testing devices are Class C, except devices for pregnancy detection, fertility testing and determining cholesterol level, and devices detecting glucose, erythrocytes, leucocytes and bacteria in urine, which are Class B. Near-patient testing devices are classified in their own right.
Rule 5 — Class A
Products for general laboratory use, accessories without critical characteristics, buffer and washing solutions, and general culture media and histological stains intended by the manufacturer to make them suitable for IVD procedures; instruments specifically intended for IVD procedures; and specimen receptacles.
Rules 6 and 7 — Class B
Rule 6 is the residual rule: devices not covered by Rules 1 to 5 are Class B. Rule 7 makes controls without a quantitative or qualitative assigned value Class B.
What MDCG 2020-16 rev.5 adds
MDCG 2020-16, the MDCG’s guidance on IVD classification rules, reached revision 5 in September 2026; rev.5 clarified the rationale and examples for Rule 7. The guidance is endorsed by the MDCG but is not legally binding.
Points from the guidance that regularly change a manufacturer’s answer:
- “High risk of propagation” (Rule 1). The guidance weighs ease of transmission, contact rate and duration of infectiousness, assessed for the general European population.
- Companion diagnostics (Rule 3(f)). The device must be essential for the safe and effective use of a corresponding medicinal product with an International Non-proprietary Name. Assays that only monitor drug levels within the therapeutic window are not companion diagnostics. Annex 2 of the guidance gives a decision flowchart.
- Self-testing (Rule 4). Collecting a specimen is not, on its own, self-testing; a lay person must perform at least part of the test procedure.
- Instruments (Rule 5(b)). An instrument with an independent measuring function that uses no additional reagents is classified by the intended purpose of the analysis, not as Class A.
- Controls (Rule 7). Stating an analyte or an expected range in the instructions for use is not an assigned value. Standalone controls only monitor laboratory procedures and do not replace the controls needed to verify the device’s performance.
Worked examples from the rule text and MDCG 2020-16
- Anti-HCV assay for screening blood donations — detects a transmissible agent to assess suitability for transfusion: Rule 1, Class D.
- Molecular RhD typing for transfusion — RH1 (D) is a listed marker: Rule 2, Class D. HLA typing for transplantation is listed by MDCG 2020-16 as Class C.
- Faecal immunochemical test for colon cancer screening — Rule 3(h), Class C.
- Troponin assay — listed under Rule 3(j), Class C.
- Blood glucose meter and strips for self-testing — Rule 4(a), Class C. A urine dipstick detecting glucose for self-testing falls in the listed exceptions: Class B.
- SARS-CoV-2 test — professional-use detection is a Rule 6 example (Class B); a SARS-CoV-2 self-test is Class C under Rule 4(a). Same analyte, different intended user, different class.
- C-reactive protein assay — Rule 6, Class B.
- PCR thermocycler or clinical chemistry analyser — Rule 5(b), Class A; its driving software takes the same class under implementing rule 1.4.
- Unassigned control sera — Rule 7, Class B. A run control with assigned values supplied for a Class C kit takes Class C under implementing rule 1.6.
Where this goes wrong
- Classifying the analyte, not the intended purpose. The SARS-CoV-2 example shows why: the class follows who uses the device and why, so a vague intended purpose produces a vague class.
- Stopping at the first matching rule. Implementing rule 1.9 requires the higher class where several rules apply. A self-test for a sexually transmitted agent has to be checked against Rules 3(a) and 4(a), and, depending on the agent, Rule 1.
- Widening the intended purpose in marketing. Adding “for screening” or “for monitoring” in the IFU or on the website can move a device into Rule 3; implementing rule 1.8 applies the highest class across all claimed purposes.
- Treating every instrument as Class A. Rule 5(b) does not cover an analyser that measures the specimen directly without separate reagents; MDCG 2020-16 classifies those by the purpose of the analysis.
- Calling an assay a companion diagnostic, or failing to. Getting Rule 3(f) wrong changes the Article 48 route, because companion diagnostics require consultation of a medicines authority or the EMA.
- Ignoring kit components. Calibrators, controls, buffers and software each need a class; Annex 1 of MDCG 2020-16 works through an ELISA system.
Record the classification as a rule-by-rule rationale in the technical documentation, citing the implementing rules and the MDCG 2020-16 example you relied on, not a single sentence asserting a class.
Frequently asked questions
How many classification rules are there under the IVDR?
Annex VIII of Regulation (EU) 2017/746 contains seven classification rules, preceded by ten implementing rules in Section 1. Rule 1 gives Class D, Rules 2 and 3 give Class C (Rule 2 gives Class D for listed blood group markers), Rule 4 covers self-testing and near-patient devices, Rule 5 gives Class A, and Rules 6 and 7 give Class B.
Is a self-test always Class C under the IVDR?
No. Rule 4(a) makes self-testing devices Class C, but pregnancy, fertility and cholesterol tests, and urine tests for glucose, erythrocytes, leucocytes and bacteria, are Class B. A self-test can also be higher: MDCG 2020-16 lists HIV antibody fingerprick self-tests as Class D, because Rule 1 also applies and implementing rule 1.9 takes the higher class.
What is the latest version of MDCG 2020-16?
Revision 5, dated September 2026, is listed on the European Commission’s MDCG guidance page. It revised the rationale and examples for Rule 7, which covers controls without an assigned value. Revision 4 had revised Rules 1, 3(m), 4(a) and 6. Always check the Commission page before relying on any revision.
How is IVD software classified?
Under implementing rule 1.4 of Annex VIII, software that drives or influences the use of a device falls into the same class as that device. Software independent of any other device is classified in its own right, using its own intended purpose against Rules 1 to 7. MDCG 2020-16 refers to MDCG 2019-11 for qualification and classification of software.
Who decides if the manufacturer and notified body disagree on the class?
Article 47(2) IVDR refers the dispute to the competent authority of the Member State where the manufacturer has its registered place of business, or, for non-EU manufacturers, where the authorised representative is established. Where the notified body is in another Member State, that authority consults the notified body’s designating authority before deciding.
Classification is the first decision in an IVDR project and the one that is hardest to undo later. With 175+ regulatory projects and 250+ products behind us, Medfins can review your intended purpose and write a rule-by-rule classification rationale before you approach a notified body. See our EU IVDR CE marking support or contact our IVDR team. Related reading: IVDR performance evaluation, IVDR transition deadlines by class, how to choose a notified body and, for devices under the MDR, our MDR classification rules with worked examples.
