---
title: IVDR Class A, B, C, and D: What Each Class Means for Your IVD Startup
description: A startup guide to the four IVDR risk classes. Class A, B, C, and D explained with conformity routes, notified body involvement, and founder implications.
authors: Tibor Zechmeister, Felix Lenhard
category: Digital Health, DiGA & Health IT
primary_keyword: IVDR Class A B C D
canonical_url: https://zechmeister-solutions.com/en/blog/ivdr-class-abcd-startup
source: zechmeister-solutions.com
license: All rights reserved. Content may be cited with attribution and a link to the canonical URL.
---

# IVDR Class A, B, C, and D: What Each Class Means for Your IVD Startup

*By Tibor Zechmeister (EU MDR Expert, Notified Body Lead Auditor) and Felix Lenhard.*

> **IVDR Regulation (EU) 2017/746 sorts in vitro diagnostic devices into four risk classes: A, B, C, and D. Class A is the lowest risk and mostly self-declared. Class D is the highest risk, covers life-threatening transmissible agents, and demands the deepest notified body and EU reference laboratory involvement. Class B and C sit in between. The class drives everything: conformity route, notified body scope, technical documentation depth, performance evaluation rigour, and post-market obligations.**

**By Tibor Zechmeister and Felix Lenhard.**

## TL;DR
- IVDR (EU) 2017/746 replaces the old IVDD directive and introduces a four-tier risk classification: A, B, C, D.
- Class A is the lowest risk and generally self-declared by the manufacturer. Sterile Class A still needs notified body involvement for the sterility aspect.
- Class B covers moderate personal risk and moderate public health risk. A notified body is required.
- Class C covers higher personal risk or moderate public health risk. A notified body is required and the scrutiny is deeper.
- Class D covers the highest risk including life-threatening transmissible agents. Notified body plus EU reference laboratory plus batch verification come into play.
- Under the old IVDD, roughly 80% of IVDs were self-declared. Under IVDR, the share flipped. The vast majority now need a notified body, and the IVD notified body pool is much smaller than the MDR pool.

## Why the class decides the founder's life (Hook)

Tibor has walked IVD founders through the new classification system since IVDR entered application. The first conversation almost always starts with sticker shock. A startup that shipped a Class A IVD under the old IVDD directive in six months, with self-declaration and a basic technical file, looks at the new IVDR class and discovers it is now Class C. That is a different universe. Notified body, deeper technical documentation, performance evaluation against a clinical endpoint, and a queue to get on a notified body's schedule.

Felix sees the startup-side consequence in Subtract to Ship coaching engagements. Founders who assumed their IVD was low risk had planned a 12-month runway. The class flip turns that into a 24 to 30 month path with a much larger regulatory budget. Planning around the wrong class is the single most expensive mistake an IVD startup can make, and it is almost always avoidable.

The class is not a bureaucratic label. It is the variable that controls the whole regulatory path.

## What IVDR actually says (Surface)

IVDR is Regulation (EU) 2017/746. It became applicable on 26 May 2022, with transitional provisions extending into later dates for legacy devices . The regulation defines four risk classes. The four classes are created by the classification rules in IVDR Annex VIII . The conformity assessment routes available for each class are set out in IVDR Articles 48 and the annexes on conformity assessment .

The four classes in plain terms:

**Class A: lowest individual risk and lowest public health risk.** Examples typically include instruments, specimen receptacles, general laboratory products, and buffers or washing solutions without specific diagnostic characteristics. Under the old IVDD this category, plus everything not listed in List A, B, or self-test, was self-declared. Under IVDR, Class A devices are still generally self-declared by the manufacturer. A full technical file is still required. A QMS under EN ISO 13485:2016+A11:2021 is still required. Risk management under EN ISO 14971:2019+A11:2021 is still required. The relief is that a notified body is not involved for the core conformity assessment. However, sterile Class A devices still require notified body scrutiny of the aspects related to sterility .

**Class B: moderate individual risk and low public health risk.** Examples are often IVDs for pregnancy self-testing, cholesterol tests, urine tests, and similar. Under IVDR, Class B devices require a notified body. The notified body audits the QMS and samples the technical documentation. This is a meaningful step up from self-declaration.

**Class C: high individual risk and moderate public health risk.** This category is where many companion diagnostics, genetic tests, and tests for sexually transmitted agents that do not cause life-threatening disease end up . Notified body involvement is deeper than Class B. Technical documentation is reviewed per product family, and the scrutiny on performance evaluation is tighter.

**Class D: highest individual risk and highest public health risk.** This category includes tests for detection of transmissible agents in blood, tissues, or organs for transfusion or transplantation, and tests for detection of life-threatening transmissible agents such as HIV, HCV, HBV, and certain other pathogens . Class D triggers the deepest regulatory scrutiny. Notified body involvement is mandatory. An EU reference laboratory performs additional verification on performance and, in some cases, batch verification. This is the heaviest conformity assessment route in the IVDR.

## A worked example (Test)

Consider a startup developing a saliva-based test for early detection of a specific oncology biomarker. The device is intended to help clinicians decide whether to start a specific cancer therapy. The test is not self-used by the patient. The test influences a treatment decision with major consequences for patient outcomes.

Under the old IVDD directive, this kind of test was frequently self-declared because it was not on List A or List B and was not a self-test. Under IVDR, the classification rules look at the intended purpose and the clinical consequence. A test that directly informs the decision to start or stop a cancer therapy is very likely Class C. If the test is explicitly a companion diagnostic for a specific medicinal product, it is in the companion diagnostic route covered by its own rule .

The practical implications for the startup:

1. A notified body is required. The IVD notified body pool is smaller than the MDR pool, so the founder has to get on a schedule early.
2. Performance evaluation replaces clinical evaluation. The startup has to demonstrate scientific validity, analytical performance, and clinical performance against defined endpoints, using samples rather than live human subjects for most aspects.
3. The technical documentation has to match Class C depth. A Class A playbook does not translate.
4. If the test is a companion diagnostic, EMA consultation is typically required .
5. Time to CE mark stretches from a few months to 18 to 30 months depending on notified body queue and performance evaluation readiness.

This is the conversation Tibor has with IVD founders almost weekly. The honest answer is rarely what the founder hoped to hear, and it is always better to hear it before the first investor meeting than after.

## The Subtract to Ship playbook (Ship)

Felix coaches IVD startups through the same sequence that works for MDR startups, adapted to the IVDR specifics. The posture is: decide the class first, plan the path second, build the evidence third.

**Step 1. Write a one-page intended purpose statement.** Not the marketing copy. The regulatory intended purpose. What exactly does the test detect or measure. Who is the intended user. Who is the intended patient. What clinical or diagnostic decision does the test inform. The IVDR class is a function of this statement. Vague intended purpose produces vague classification, and vague classification produces rework later.

**Step 2. Map the intended purpose to the IVDR classification rules.** Use IVDR Annex VIII rules . Tibor noted in a recent interview that IVDR has far fewer classification rules than MDR. The rule set is shorter but the decisions have bigger consequences per rule. Walk the rules in order and document which rule applies and why.

**Step 3. Write a classification justification document.** One page per rule that applies. Cite the rule. State the class. State the reasoning. Sign and date it. This document is the first thing a notified body will ask for and the first thing an auditor will scrutinise.

**Step 4. Decide whether a notified body is required and plan for the queue.** Everything above Class A needs a notified body, and sterile Class A needs one for the sterility aspect. Start the notified body conversation before the QMS is fully built. Do not wait until the technical file is finished.

**Step 5. Build the QMS around EN ISO 13485:2016+A11:2021.** The QMS is the same foundation as for MDR devices. An IVD QMS has IVD-specific procedures for performance evaluation, but the backbone is the same.

**Step 6. Budget for performance evaluation as a major line item.** Performance evaluation is the IVDR equivalent of clinical evaluation. It costs time and money. It is not optional. It scales with class.

**Step 7. Do not over-classify, do not under-classify.** Both are expensive. Over-classification burns budget on a route the device does not need. Under-classification gets caught by the notified body and resets the project. The classification justification document is the discipline that protects against both failures.

## Reality Check

1. Do you have a one-page regulatory intended purpose statement for your IVD, separate from the marketing description?
2. Have you identified which IVDR Annex VIII rule applies to your device and written down the reasoning?
3. Have you decided on a class and produced a classification justification document signed by a named person?
4. If your class is B, C, or D, have you approached notified bodies about schedule and scope?
5. Do you know whether your device is a companion diagnostic under IVDR, and if so, have you factored EMA consultation into the plan?
6. Is your QMS built around EN ISO 13485:2016+A11:2021 with IVD-specific procedures for performance evaluation?
7. Does your runway and investor plan reflect the actual class, or a hoped-for class from the IVDD days?
8. If you believe you are Class A, have you checked whether sterility changes the notified body picture?

If any answer is "no" or "not yet," that is the next thing to work on before anything else on the roadmap.

## Frequently Asked Questions

**Is IVDR Class A the same as MDR Class I?**
Class A under IVDR is similar in posture to MDR Class I in the sense that manufacturers generally self-declare. It is not the same in scope. The IVDR rules and device categories are entirely different, and sterile Class A triggers notified body involvement for the sterility aspect just as sterile Class I does under MDR.

**Can a Class B IVD be self-declared?**
No. Class B and above all require a notified body under IVDR. Only Class A non-sterile can be fully self-declared.

**Why did so many IVDs move up in class from IVDD to IVDR?**
Under the old IVDD directive, the default was self-declaration unless the device was on List A, List B, or was a self-test. Under IVDR, the classification is rule-based and tied to risk. The effect is that the share of IVDs requiring notified body involvement shifted from roughly 20 percent under IVDD to roughly 80 to 90 percent under IVDR, according to impact assessments at the time of the regulation. Exact figures should be verified against the most recent Commission and MDCG publications .

**How do I find an IVD notified body?**
The list of designated IVD notified bodies is published on NANDO. The pool is smaller than for MDR. Start the conversation early, ideally 12 months before you need a quote, and be prepared to wait in the queue.

**What is performance evaluation and how is it different from clinical evaluation?**
Performance evaluation is the IVDR equivalent of clinical evaluation under MDR. It consists of scientific validity, analytical performance, and clinical performance. It uses samples such as blood, saliva, or tissue to demonstrate diagnostic accuracy rather than live human subjects for most aspects.

**What if my device is borderline between classes?**
Document the borderline in the classification justification. Pick the higher class when the reasoning is close. Raise the question with your notified body early. Do not leave it for the audit.

## Related reading
- [MDR device classification explained](/blog/mdr-device-classification-explained) provides the MDR analogue framework that IVD founders coming from MDR will recognise.
- [Class I medical devices under MDR](/blog/class-i-medical-devices-under-mdr) explains the self-declaration posture that IVDR Class A echoes.
- [What is a notified body](/blog/what-is-notified-body) covers the role notified bodies play in any regulated conformity route, including IVDR Class B, C, and D.

## Sources
1. Regulation (EU) 2017/746 on in vitro diagnostic medical devices, consolidated text. Classes A, B, C, D, Annex VIII classification rules, conformity assessment annexes. 
2. Regulation (EU) 2017/745 on medical devices, consolidated text. Referenced for MDR analogy.
3. EN ISO 13485:2016+A11:2021 – Medical devices, quality management systems.
4. EN ISO 14971:2019+A11:2021 – Medical devices, application of risk management.
5. Tibor Zechmeister follow-up interview, April 2026. Section 5, IVDR overlap with MDR.

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*This post is part of the [Digital Health, DiGA & Health IT](https://zechmeister-solutions.com/en/blog/category/digital-health) cluster in the [Subtract to Ship: MDR Blog](https://zechmeister-solutions.com/en/blog). For EU MDR certification consulting, see [zechmeister-solutions.com](https://zechmeister-solutions.com).*