The IVDR, Regulation (EU) 2017/746, has applied since 26 May 2022. It replaced the list-based approach of Directive 98/79/EC with classification rules, and the European Commission's factsheet for IVD manufacturers estimates that as a result around 85% of all IVDs need notified body oversight. MDCG 2020-16, the MDCG guidance on IVD classification, is now at revision 5.
The class decides who assesses the device and how much evidence is reviewed. This article explains the four classes, the seven rules in Annex VIII, how software is classified, and what each class triggers.
The four classes
Article 47 sorts IVDs into four classes, based on intended purpose and inherent risk:
| Class | Risk | Conformity assessment |
|---|---|---|
| A | Low individual and low public health risk | Manufacturer's own declaration; a notified body is involved only for sterile devices, limited to sterility aspects (Art. 48(10)) |
| B | Moderate individual and/or low public health risk | Notified body, Annex IX Chapters I and III, with technical documentation assessed for at least one representative device per category (Art. 48(9)) |
| C | High individual and/or moderate public health risk | Notified body, Annex IX Chapters I and III, with technical documentation assessed for at least one representative device per generic device group (Art. 48(7)) |
| D | High individual and high public health risk | Notified body, Annex IX, or Annex X with Annex XI (Art. 48(3) and (4)) |
Sources: IVDR Articles 47 and 48; European Commission factsheet.
Intended purpose decides the class
The classification rules are applied according to the intended purpose of the device (Annex VIII, Section 1.1). Some implementing rules matter in most cases:
devices used in combination with another device are classified separately, and so are accessories;
calibrators and controls with assigned values take the class of the device they are intended for;
if several rules, or several intended purposes, apply, the highest class applies.
In our view, the intended purpose should name the analyte, the specimen, the target population, the intended user, the setting and the clinical decision before any rule is chosen. A vague intended purpose leaves the classification open to challenge.
The seven rules
| Rule | Covers | Class |
|---|---|---|
| 1 | Detection of transmissible agents in blood, blood components, cells, tissues or organs to assess suitability for transfusion or transplantation; agents causing life-threatening disease with a high risk of propagation; infectious load of a life-threatening disease where monitoring is critical to patient management | D |
| 2 | Blood grouping or tissue typing to ensure immunological compatibility | C, or D for specified markers in the ABO, Rhesus, Kell, Kidd and Duffy systems |
| 3 | Specified purposes in indents (a) to (m), including companion diagnostics, disease staging, cancer screening, diagnosis or staging, human genetic testing and screening for congenital disorders | C |
| 4 | Self-testing: C, except pregnancy, fertility and cholesterol testing, and detection of glucose, erythrocytes, leucocytes and bacteria in urine, which are B. Near-patient testing is classified in its own right | B or C |
| 5 | Products for general laboratory use, instruments intended specifically for IVD procedures and specimen receptacles | A |
| 6 | Devices not covered by the other rules | B |
| 7 | Controls without an assigned quantitative or qualitative value | B |
Source: IVDR Annex VIII.
Each rule has precise wording and conditions, so the table is a starting point, not a substitute for reading the rule. For example, a self-test that also falls under Rule 1 stays in class D.
Software
Under Annex VIII Section 1.4, software that drives or influences the use of a device falls in the same class as that device. Software that is independent of any other device is classified in its own right.
Qualification comes first: is the software an IVD at all? MDCG 2019-11 Rev.1 covers qualification and classification of medical device software, including software that is an IVD. MDCG 2020-16 gives examples, such as software that generates an estimated glomerular filtration rate (eGFR) or albumin creatinine ratio for staging acute kidney injury.
In our view, decide whether software drives an instrument or stands alone before borrowing the instrument's class. Software that does its own diagnostic job is classified on its own purpose, wherever it runs.
Companion diagnostics
Under Article 2(7), a companion diagnostic is essential for the safe and effective use of a corresponding medicinal product, to identify patients most likely to benefit or at increased risk of serious adverse reactions. It falls under Rule 3 and is class C. The notified body must consult a medicines authority as part of the assessment.
According to MDCG 2020-16, devices used to set the dose of a medicine for patients already eligible to receive it are not companion diagnostics. Annex 2 of the guidance gives a flowchart to help decide.
What each class triggers
| Class | Notified body | Post-market reporting |
|---|---|---|
| A (non-sterile) | None | PMS report (Art. 80) |
| A (sterile) | Sterility aspects only | PMS report (Art. 80) |
| B | Yes | PMS report (Art. 80) |
| C | Yes | PSUR (Art. 81) |
| D | Yes, plus EU reference laboratory testing where one is designated, and expert panel consultation in specified cases | PSUR (Art. 81) |
Sources: IVDR Articles 48, 80 and 81; European Commission factsheet.
Our articles on IVD CE marking and post-market surveillance under the IVDR cover the conformity assessment route and the reporting duties in more detail.
Manufacturers outside the EU also need an EU authorised representative under Article 11 of the IVDR. MedQAIR's Digital AR service covers both medical devices and IVDs.
A hypothetical example
Hypothetical example: a Dutch start-up develops standalone software that calculates eGFR from laboratory creatinine results to stage acute kidney injury, for use by clinicians.
Qualification: the software provides information on a physiological state for a medical purpose, so it is an IVD.
Independent or driving: it does not control an analyser, so it is classified in its own right.
Rule: disease staging falls under Rule 3, so it is class C. MDCG 2020-16 gives this as an example.
Self-testing: it is for professional use, so Rule 4 does not apply.
Consequence: notified body assessment under Annex IX, with technical documentation sampled per generic device group, and a PSUR.
If the company later adds a patient-facing version, the classification must be reassessed for self-testing.
When the notified body disagrees
Under Article 47(2), a dispute between the manufacturer and the notified body about the application of Annex VIII is referred to the competent authority of the Member State where the manufacturer has its registered place of business.
Conclusion
IVDR classification follows the intended purpose through seven rules, with the highest applicable class winning. Software is classified either with the device it drives or in its own right. The class then sets the notified body's role and the post-market reporting.
In our view, a good classification record lists every rule considered, explains why each does or does not apply, and is revisited whenever the claims change.
If you need help classifying your IVD, our regulatory strategy team can help, or contact MedQAIR.
Frequently asked questions
How many classes does the IVDR have?
Four: A, B, C and D, from lowest to highest risk.
Which IVDs need a notified body?
All class B, C and D devices, and class A devices placed on the market sterile (for sterility aspects only).
Are self-tests always class C?
No. Most are, but pregnancy, fertility and cholesterol self-tests, and urine tests for glucose, erythrocytes, leucocytes and bacteria are class B. A self-test covered by Rule 1 is class D.
How is IVD software classified?
Software that drives or influences a device takes that device's class. Independent software is classified in its own right under the Annex VIII rules.
Is a test used to set a medicine's dose a companion diagnostic?
Not usually. According to MDCG 2020-16, tests used to set the dose for patients already eligible for a medicine are not companion diagnostics.
