Working through the IVDR classification rules

The class of an in vitro diagnostic medical device under Regulation (EU) 2017/746 follows from its intended purpose, applied against the seven classification rules in Annex VIII. Article 47(1) divides devices into classes A, B, C and D according to intended purpose and inherent risk, and states that classification is carried out in accordance with Annex VIII.¹ Class D carries the highest risk and class A the lowest. Where more than one rule applies, the rule giving the higher class prevails, so the work of classification is a matter of reading every rule against the stated purpose rather than stopping at the first match.

How Article 47 frames classification

Article 47 does three things. It sets the four classes and points to Annex VIII for the rules. It provides a route for disputes between a manufacturer and a notified body arising from the application of Annex VIII, which are referred for decision to the competent authority of the Member State where the manufacturer has its registered place of business.¹ Where the manufacturer has no registered place of business in the Union and has not designated an authorised representative, the matter goes to the competent authority of the Member State where the authorised representative referred to in Annex IX, Section 2.2 has its registered place of business.¹

Where the notified body is established in a different Member State from the manufacturer, the competent authority adopts its decision after consulting the competent authority that designated the notified body. The deciding authority notifies the Medical Device Coordination Group and the Commission of its decision, and the decision is made available upon request.¹

Article 47 also allows the classification outcome to be set centrally. At the request of a Member State, and after consulting the MDCG, the Commission decides by implementing act on the application of Annex VIII to a given device or category or group of devices.¹ The Commission may also decide that a device, category or group is reclassified by way of derogation from Annex VIII, for reasons of public health based on new scientific evidence or on information arising from vigilance and market surveillance activities.¹ The Commission may act on its own initiative on both points, and may adopt implementing acts to resolve issues of divergent interpretation and practical application of Annex VIII.¹

The implementing rules in Annex VIII

Section 1 of Annex VIII governs how the rules are applied. The application of the classification rules is governed by the intended purpose of the device.¹ Where a device is intended to be used in combination with another device, the rules apply separately to each device, and accessories are classified in their own right separately from the device with which they are used.¹

Software that drives a device or influences its use falls within the same class as that device. Software independent of any other device is classified in its own right.¹ Calibrators intended to be used with a device are classified in the same class as that device.¹ Control materials with quantitative or qualitative assigned values, whether for one analyte or several, take the class of the device.¹ Controls without an assigned value are dealt with separately by Rule 7.

Three further implementing rules determine the outcome where the rules overlap. The manufacturer takes into consideration all classification and implementing rules in order to establish the proper classification.¹ Where the manufacturer states multiple intended purposes and the device falls into more than one class as a result, it is classified in the higher class, and where several classification rules apply to the same device the rule resulting in the higher classification applies.¹ Each classification rule applies to first line assays, confirmatory assays and supplemental assays alike.¹

Class D under Rules 1 and 2

Rule 1 places in class D devices intended for any of the following purposes:

• detection of the presence of, or exposure to, a transmissible agent in any of the following or in any of their derivatives, to assess their suitability for transfusion, transplantation or cell administration
  • blood
  • blood components
  • cells
  • tissues
  • organs
• detection of the presence of, or exposure to, a transmissible agent that causes a life-threatening disease with a high or suspected high risk of propagation.
• determining the infectious load of a life-threatening disease where monitoring is critical in the process of patient management.¹

Rule 2 covers devices for blood grouping, for determining foeto-maternal blood group incompatibility, or for tissue typing to ensure immunological compatibility of the following where intended for transfusion, transplantation or cell administration.

• blood
• blood components
• cells
• tissue
• organs

Those devices are class C as a general matter.¹ They are class D when intended to determine markers in the following systems.¹

• the ABO system [A (ABO1), B (ABO2), AB (ABO3)]
• the Rhesus system [RH1 (D), RHW1, RH2 (C)]
• the Rhesus system [RH3 (E), RH4 (c), RH5 (e)]
• the Kell system [Kel1 (K)]
• the Kidd system [JK1 (Jka), JK2 (Jkb)]
• the Duffy system [FY1 (Fya), FY2 (Fyb)]

Class C under Rule 3

Rule 3 is the longest rule and captures most assays with serious patient management consequences. Devices are class C if they are intended for any of the following:

• detecting the presence of, or exposure to, a sexually transmitted agent.
• detecting the presence in cerebrospinal fluid or blood of an infectious agent without a high or suspected high risk of propagation.
• detecting the presence of an infectious agent where there is a significant risk that an erroneous result would cause death or severe disability to the individual, foetus or embryo being tested, or to the individual’s offspring.
• pre-natal screening of women to determine their immune status towards transmissible agents.
• determining infective disease status or immune status, where an erroneous result risks a patient management decision resulting in a life-threatening situation for the patient or the patient’s offspring.
• use as companion diagnostics.
• disease staging, where an erroneous result risks a patient management decision resulting in a life-threatening situation for the patient or the patient’s offspring.
• screening, diagnosis or staging of cancer.
• human genetic testing.
• monitoring of levels of medicinal products, substances or biological components, where an erroneous result risks a patient management decision resulting in a life-threatening situation for the patient or the patient’s offspring.
• management of patients suffering from a life-threatening disease or condition.
• screening for congenital disorders in the embryo or foetus.
• screening for congenital disorders in new-born babies where failure to detect and treat such disorders could lead to life-threatening situations or severe disabilities.¹

Two items in this list are worth separating out for readers coming from other regimes. Companion diagnostics are class C by operation of Rule 3(f), regardless of the medicinal product concerned.¹ Human genetic testing is class C by operation of Rule 3(i), with no threshold of clinical consequence attached to that item.¹

Self-testing, near-patient testing and the residual classes

Rule 4(a) places devices intended for self-testing in class C. The exceptions are devices for the detection of pregnancy, for fertility testing and for determining cholesterol level, and devices for the detection of glucose, erythrocytes, leucocytes and bacteria in urine. Those exceptions are class B.¹ Rule 4(b) states that devices intended for near-patient testing are classified in their own right. The setting of use therefore does not by itself raise the class.¹

Rule 5 assigns class A to three groups. The first is products for general laboratory use, accessories which possess no critical characteristics, buffer solutions, washing solutions, and general culture media and histological stains, where the manufacturer intends them to be suitable for in vitro diagnostic procedures relating to a specific examination.¹ The second is instruments intended by the manufacturer specifically for in vitro diagnostic procedures. The third is specimen receptacles.¹

Rule 6 is residual: devices not covered by the other rules are class B.¹ Rule 7 assigns class B to controls without a quantitative or qualitative assigned value.¹

What the class determines in the transitional and application provisions

Class drives the dates in Article 110 for devices still relying on Directive 98/79/EC. Devices holding a certificate issued under that Directive and valid by virtue of Article 110(2) may be placed on the market or put into service until 31 December 2027.¹ Devices that needed no notified body under the Directive, that had a declaration of conformity drawn up before 26 May 2022, and that require notified body involvement under the Regulation may be placed on the market until 31 December 2027 for class D, 31 December 2028 for class C, and 31 December 2029 for class B and for class A devices placed on the market in sterile condition.¹

Those dates apply only where the conditions in Article 110(3c) are met. The device must continue to comply with Directive 98/79/EC, there must be no significant changes in design and intended purpose, and the device must not present an unacceptable risk.¹ The manufacturer must have had a quality management system in place in accordance with Article 10(8) by 26 May 2025.¹ A formal application to a notified body under Annex VII, Section 4.3 was due by 26 May 2025 for certificate-holding devices and class D devices. For class C devices the date was 26 May 2026, and for class B and class A sterile devices it was 26 May 2027.¹ The written agreement with the notified body was due by 26 September 2025, 26 September 2026 and 26 September 2027 respectively.¹

Article 110(3d) makes the Regulation’s requirements on post-market surveillance, market surveillance, vigilance and registration apply to these devices in place of the corresponding Directive requirements.¹ Article 113(3)(f) sets the application of that paragraph at 6 months from publication of the notice that the relevant electronic system is functional.¹ Class also fixed the start dates for the UDI carrier obligation in Article 24(4). That obligation has applied since 26 May 2023 for class D devices and since 26 May 2025 for class B and class C devices, and it applies from 26 May 2027 for class A devices.¹

Questions people also ask

Does the analyte or the intended purpose decide the IVDR class?

The intended purpose decides. Annex VIII, Section 1.1 states that application of the classification rules is governed by the intended purpose of the devices.¹ The same analyte can therefore sit in different classes depending on what the manufacturer claims the device does. Where the manufacturer states multiple intended purposes and the device falls into more than one class as a result, Section 1.8 places it in the higher class.¹

How are companion diagnostics classified?

Rule 3(f) classifies devices intended to be used as companion diagnostics as class C.¹ Where another rule would give a higher class for the same device, Section 1.9 gives effect to the rule producing the higher classification.¹

Are calibrators and control materials classified with the assay?

Calibrators intended to be used with a device take the class of that device under Section 1.5, and control materials with quantitative or qualitative assigned values take the class of the device under Section 1.6.¹ Controls without an assigned value are class B under Rule 7.¹ Accessories are classified in their own right, separately from the device with which they are used.¹

Who resolves a disagreement over classification with a notified body?

Article 47(2) refers the dispute to the competent authority of the Member State where the manufacturer has its registered place of business.¹ Where the notified body sits in another Member State, that authority decides after consulting the authority that designated the notified body.¹ The decision is notified to the MDCG and the Commission and is made available upon request.¹

Can the Commission change the class of a device type?

Yes. Article 47(3)(b) allows the Commission to reclassify a device or a category or group of devices by implementing act, by way of derogation from Annex VIII. This follows a request from a Member State and consultation of the MDCG.¹ The grounds are public health based on new scientific evidence, or information arising in vigilance and market surveillance activities. The Commission may also act on its own initiative under Article 47(4).¹

Footnotes

1. Regulation (EU) 2017/746 of the European Parliament and of the Council of 5 April 2017 on in vitro diagnostic medical devices and repealing Directive 98/79/EC and Commission Decision 2010/227/EU. Consolidated version of 2025-01-10. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02017R0746-20250110 ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷ ↩¹⁸ ↩¹⁹ ↩²⁰ ↩²¹ ↩²² ↩²³ ↩²⁴ ↩²⁵ ↩²⁶ ↩²⁷ ↩²⁸ ↩²⁹ ↩³⁰ ↩³¹ ↩³² ↩³³ ↩³⁴ ↩³⁵ ↩³⁶ ↩³⁷ ↩³⁸ ↩³⁹ ↩⁴⁰ ↩⁴¹ ↩⁴² ↩⁴³ ↩⁴⁴ ↩⁴⁵ ↩⁴⁶ ↩⁴⁷ ↩⁴⁸