The IVDR classification rules live in Annex VIII of Regulation (EU) 2017/746. There are far fewer rules than the 22 classification rules in MDR Annex VIII. Each rule assigns a risk class A, B, C, or D based on the intended purpose of the IVD, the clinical decision the device informs, and the public health consequence of a wrong result. This post walks the rule set at a high level so IVD startups can produce a defensible classification justification before they commit to a regulatory plan.

By Tibor Zechmeister and Felix Lenhard.

TL;DR

  • IVDR classification rules are in Annex VIII of Regulation (EU) 2017/746. The rule count is significantly smaller than MDR's 22 rules .
  • The classification rules assign the device to Class A, B, C, or D. The class determines the conformity assessment route and the notified body involvement.
  • Rule 1 in IVDR Annex VIII covers the highest risk category including detection of transmissible agents in blood for transfusion and life-threatening transmissible agents .
  • A rule for companion diagnostics, a rule for self-testing, a rule for near-patient testing, and a catch-all rule round out the set .
  • The classification is always anchored in the intended purpose. A vague intended purpose produces an unstable classification.
  • The deliverable is a signed classification justification document. Every rule applied, every decision documented.

Why the rule walk matters (Hook)

Tibor has seen more IVD startups mis-classify their device than correctly classify it on the first attempt. Not because the rules are hidden. Because founders read the rules once, pick the class they hoped for, and move on. The notified body then reads the same rules with 20 years of experience and arrives at a different answer. The project resets.

Felix frames the Subtract to Ship principle the same way for IVD founders as for MDR founders. Classification is not paperwork. Classification is the load-bearing decision that determines everything downstream: technical documentation scope, performance evaluation rigour, notified body involvement, post-market obligations, and honestly, whether the company survives the regulatory path on the runway it has.

Working the rules properly is cheaper than working them improperly. The rule walk is the cheapest hour a founder will spend this quarter.

What IVDR actually says (Surface)

IVDR Annex VIII contains the classification rules for in vitro diagnostic medical devices. Tibor noted in a recent interview that IVDR has significantly fewer classification rules than MDR. The commonly cited figure is seven rules in IVDR Annex VIII, compared to 22 rules in MDR Annex VIII .

The general structure of the IVDR rule set, at a high level:

Rule 1: highest-risk transmissible agents and blood grouping for critical transfusion decisions. This rule places devices in Class D when they detect the presence of or exposure to transmissible agents in blood, blood components, cells, tissues or organs intended for transfusion or transplantation. It also covers detection of life-threatening transmissible agents with high or suspected high propagation risk, such as HIV, HCV, HBV, HTLV, and similar . The underlying principle is that a wrong result has catastrophic public health consequences.

Rule on detection of transmissible agents without life-threatening character, or for staging of disease. This rule typically places devices in Class C. Examples include tests for sexually transmitted agents that are not in the life-threatening category, certain cancer staging tests, and tests that inform the choice of therapy .

Rule on companion diagnostics. Companion diagnostics are IVDs intended to identify patients who are suitable, or unsuitable, for a specific medicinal product. This rule places companion diagnostics in Class C . There is a separate obligation to consult the European Medicines Agency on the companion diagnostic's suitability for the intended medicinal product.

Rule on self-testing and near-patient testing. This rule addresses devices used by lay users at home or by healthcare professionals outside a central laboratory. The class depends on what the test detects and the clinical consequence. A pregnancy self-test lands in a different class than a self-test for a life-threatening condition.

Catch-all and other rules. The remaining rules cover reagents, calibrators, control materials, instruments, and any device not specifically classified by an earlier rule. The catch-all typically lands these in Class A if the risk is low and the public health consequence is minor .

The governing principle across all rules is the intended purpose. IVDR defines intended purpose in line with the general regulatory definition used in MDR Article 2(12): "intended purpose means the use for which a device is intended according to the data supplied by the manufacturer on the label, in the instructions for use or in promotional or sales materials or statements and as specified by the manufacturer in the clinical evaluation" .

A worked example (Test)

Consider a startup developing a PCR-based test for detection of a specific respiratory pathogen. The pathogen is not on the life-threatening list. The test is used in hospital laboratories to inform antibiotic treatment decisions. The test is not a self-test and is not a companion diagnostic for a specific medicinal product.

Walking the rules:

  • Rule 1 for life-threatening transmissible agents does not apply. The pathogen is not on the relevant list.
  • The rule for detection of transmissible agents that inform therapy decisions or staging applies. A wrong result leads to wrong antibiotic choice, which has clinical consequences but is not in the catastrophic public health category.
  • The companion diagnostic rule does not apply. The test is not tied to a specific medicinal product.
  • The self-testing rule does not apply. Use is professional, in a hospital laboratory.

The probable class is C .

Consequences for the startup:

  1. Notified body involvement is required.
  2. Technical documentation follows the Class C route.
  3. Performance evaluation has to demonstrate scientific validity, analytical performance, and clinical performance.
  4. The classification justification document has to cite each rule considered and each decision made.
  5. Runway and budget plan around Class C, not Class A.

This is the disciplined rule walk. It takes one to two hours with someone who has done it before and saves months of rework.

The Subtract to Ship playbook (Ship)

Step 1. Write the regulatory intended purpose in one page. The class is a function of the intended purpose. If the intended purpose is vague, the class is unstable. Include what the test detects, who the intended user is, what clinical decision the result informs, and the patient population.

Step 2. Read IVDR Annex VIII in full. Not a summary. The actual text. Tibor's rule is that any founder who has not read Annex VIII in full is not yet in a position to discuss classification.

Step 3. Walk the rules in order. For each rule, ask: does this rule apply to my device given the intended purpose? If yes, what class does it assign. If no, why not. Document the answer.

Step 4. If more than one rule applies, pick the highest class. This is the standard rule of thumb across medical device regulations. A device that falls under multiple rules is classified at the highest class any rule assigns.

Step 5. Produce a classification justification document. One page per rule considered. Cite the rule. State whether it applies. State the class. Sign and date. This is the first artifact any notified body or regulatory advisor will ask to see.

Step 6. Pressure test the classification. Share the document with someone who has walked this path before. A notified body pre-submission meeting is an option. An independent regulatory advisor is another. Tibor and the Zechmeister Strategic Solutions team review classification documents for startups as a standard engagement.

Step 7. Do not classify by hope. Founders often arrive at a class because it fits the runway. The class does not care about the runway. Better to re-plan the runway than to mis-classify and reset the project six months in.

Reality Check

  1. Have you read IVDR Annex VIII in full, not a summary, in the last three months?
  2. Do you have a one-page regulatory intended purpose that a third party could read and classify from?
  3. Have you walked the rules in order and documented which apply and which do not?
  4. Have you applied the rule that when more than one rule applies, the highest class wins?
  5. Do you have a signed classification justification document with a named author?
  6. Has anyone with notified body experience reviewed the classification?
  7. If your device involves transmissible agents, have you explicitly checked whether Rule 1 for life-threatening agents applies?
  8. If your device informs a medicinal product decision, have you explicitly checked whether the companion diagnostic rule applies?

If any answer is "no," that is the next work item, full stop.

Frequently Asked Questions

How many classification rules does IVDR Annex VIII contain? The commonly cited figure is seven rules, significantly fewer than MDR Annex VIII which contains 22 rules. The exact rule set should be verified against the current consolidated text of Regulation (EU) 2017/746 .

What if my device fits more than one rule? Apply the highest class any applicable rule assigns. This is the standard rule across EU medical device classification.

Do the IVDR classification rules use the same "intended purpose" concept as MDR? Yes. Intended purpose is the anchor for classification under both regulations. A vague intended purpose produces a vague classification, and rework follows.

Is there an MDCG guidance document on IVDR classification? MDCG has published guidance on IVDR classification. The title and current version should be checked on the Commission's MDCG guidance page before citing .

What is the difference between classification and conformity assessment route? Classification assigns the device to a risk class. The conformity assessment route describes how compliance is demonstrated. The class determines which routes are available.

Can classification change during development? Yes. If the intended purpose changes, the class can change. A pivot that narrows or broadens the intended user, the patient population, or the clinical decision can move the device up or down a class. Update the classification justification whenever the intended purpose changes.

Sources

  1. Regulation (EU) 2017/746 on in vitro diagnostic medical devices, consolidated text. Annex VIII classification rules.
  2. Regulation (EU) 2017/745 on medical devices, consolidated text. Referenced for MDR parallel.
  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 rule-count observation.