You’re developing an in vitro diagnostic (IVD) device and wondering about the differences between IVDR classes A, B, C, and D and how they affect your performance evaluation? Under the In Vitro Diagnostic Regulation (IVDR, EU 2017/746), your classification determines the depth of scientific validity, analytical performance, and clinical evidence required. If you want to avoid back‑and‑forths with your Notified Body, it’s essential to understand these differences early when designing your performance evaluation strategy. This article walks you through each class to help you align your evidence level and secure CE marking.
How are IVDR classes defined?
Before discussing class differences, it’s important to recall how the IVDR classification system (A, B, C, D) works. According to Regulation (EU) 2017/746, IVDs are classified based on their intended use and potential risks to patients and public health from the lowest (class A) to the highest (class D). The classification rules, detailed in Annex VIII of the IVDR and clarified by MDCG guidance documents, consider:
- The type of marker.
- The clinical purpose.
- The mode of use (self‑test, routine test, screening, confirmatory test, etc.).
- The impact of an incorrect result.
Getting your classification right is the first mandatory step before designing your performance evaluation plan.
IVDR classes and their impact on performance evaluation
While the IVDR imposes the same general framework for all devices (scientific validity, analytical performance, and clinical performance) the depth of evidence depends on the risk class. Each manufacturer must prepare a Performance Evaluation Plan (PEP) and a Performance Evaluation Report (PER) covering:
- The link between the analyte and the targeted clinical condition (scientific validity).
- The reliability and reproducibility of the test signal (analytical performance: accuracy, precision, sensitivity, specificity, limits of detection, interferences, stability, etc.).
- The demonstration that results support clinical decision‑making (clinical performance), using literature, real‑world data, or dedicated studies.
Where IVDR classes differ most is in the level of detail required, the extent of clinical data, the involvement of a Notified Body, and the frequency of PER updates through post‑market surveillance (PMS) and Post‑Market Performance Follow‑up (PMPF).
Class A: Proportionate requirements for low‑risk devices
Class A devices pose minimal risk to patients and public health. Examples include laboratory instruments, specimen receptacles, or basic reagents. Most may be self‑certified by the manufacturer, with Notified Body involvement only for sterile products.
Performance evaluation for class A typically involves:
- Demonstrating scientific validity through published literature and state‑of‑the‑art reviews.
- Documenting analytical performance proportionally (e.g., stability, precision, limits of measurement, interferences).
- Relying on literature or intended‑use justification for clinical performance, without major clinical studies.
A PER is still mandatory but remains concise and mostly internal, updated as needed when field data or significant device changes arise.
Class B: More structured PEP and PER
Class B IVDs pose moderate risk to individuals and low risk to public health (e.g., routine diagnostic tests or certain self‑tests). Here, a Notified Body is usually involved in assessing the quality system and representative technical documentation, including the performance evaluation.
Key differentiators of class B include:
- A more detailed PEP aligned with the intended use and target population.
- A full PER addressing scientific validity, analytical, and, if needed, clinical performance.
- Possible targeted clinical performance studies when literature or equivalence data are insufficient.
Post‑market, Periodic Safety and Performance Reports (PMSR) are expected, and the PER must be updated when new relevant data arise.
Class C: High expectations for clinical data
Class C devices present high individual risk and moderate public health risk. These include many genetic tests, cancer markers, and companion diagnostics. Here, the differences between IVDR classes become most evident, especially in terms of required clinical evidence.
Performance evaluation for class C generally includes:
- Robust scientific validity, supported by an extensive literature review and possibly preclinical or proof‑of‑concept data.
- Deep analytical performance characterization: sensitivity, specificity, robustness, reproducibility (inter‑site, inter‑lot), and justified study design.
- Dedicated prospective or retrospective clinical performance studies when existing data do not sufficiently demonstrate clinical relevance.
The PER must integrate all evidence sources. A Summary of Safety and Performance (SSP) may be required, and ongoing PSUR and PMPF activities must feed into regular (often annual) PER updates reviewed by the Notified Body.
Class D: Maximum scrutiny and external verification
Class D devices carry the highest risks, for example, tests detecting infectious agents of major public health concern. Erroneous results can have serious consequences, so the IVDR sets the highest bar for these products.
Expectations for class D include:
- A comprehensive PEP encompassing the full lifecycle, including PMPF strategy.
- An exhaustive PER with extensive analytical studies (robustness, extreme performance limits, cross‑validation) and typically multicentric clinical trials.
- Possible involvement of EU reference laboratories or external experts to confirm findings.
The Notified Body may consult expert panels, and post‑market surveillance involves frequent PSURs, vigilance analyses, and PER updates. The IVDR class difference here translates to unparalleled levels of documentation, testing, and oversight.
How to adapt your performance evaluation strategy
Not all manufacturers face the same evidence burden. As the IVDR class increases, the performance evaluation must rely increasingly on clinical and real‑world data. To build an effective strategy:
- Secure your correct IVDR classification early, ideally with expert support.
- Design a PEP proportional to the risk, assessing whether your evidence level would satisfy a Notified Body for that class.
- Integrate post‑market elements (PMS, PMPF, PSUR) from the start, and plan PER update frequency accordingly (more frequent for classes C and D).
Why partner with a third‑party lab like Amarok?
Because of these rising expectations, many manufacturers now rely on specialized labs for analytical performance evaluation. An ISO/IEC 17025‑accredited laboratory ensures methodological rigor, traceability, and compliance, all highly valued by Notified Bodies.
Amarok Biotechnologies is France’s first EN ISO/IEC 17025:2017‑accredited lab dedicated to analytical performance evaluation for IVDs. The team supports manufacturers, consultants, and start‑ups to:
- Design measurement programs aligned with their IVDR class.
- Generate robust analytical data suitable for inclusion in the PER.
- Supply PMPF evidence and help maintain regulatory files.
Key takeaways
- The IVDR divides IVDs into classes A–D, determining how deep your performance evidence must go.
- All devices must show scientific validity, analytical performance, and clinical performance, but the depth increases with risk.
- Classes A and B require structured documentation, with more Notified Body involvement starting from class B.
- Classes C and D demand extensive analytical and clinical data, a strong PMPF plan, and frequent PER updates.
- Confirming your correct IVDR class and partnering with an ISO/IEC 17025‑accredited lab like Amarok helps align your performance evaluation strategy with regulatory expectations.
Want to check if your evidence level matches your IVDR class?
Partner with a lab like Amarok Biotechnologies to design analytical studies and strengthen your PER before engaging with your Notified Body.