Laboratory-developed tests, or LDTs, do not sit outside the EU In Vitro Diagnostic Medical Devices Regulation. When a test has an in vitro diagnostic intended purpose, it is an IVD. A health institution established in the European Union may manufacture and use that IVD without following the normal CE-marking pathway only when all applicable conditions of Article 5(5) are met.
In EU regulatory terminology, “in-house IVD” is therefore more precise than “LDT”. The health institution exemption applies to devices manufactured and used within the same health institution and legal entity, on a non-industrial scale.
MDCG 2023-1 explains how health institutions and competent authorities should interpret these conditions. It is guidance rather than legally binding legislation. The consolidated IVDR and applicable national provisions remain the primary legal sources.
Key point: As of August 2026, most Article 5(5) requirements already apply. The remaining deferred condition is Article 5(5)(d), which requires a documented justification that the target patient group’s specific needs cannot be met, or cannot be met at the appropriate level of performance, by an equivalent device available on the market. This condition becomes applicable on 26 May 2028.
Is an LDT different from an IVD under the IVDR?
An IVD is a regulatory product category defined by Article 2(2) of the IVDR. “Laboratory-developed test” describes how a test has been developed or manufactured, but it does not create a separate exclusion from the Regulation.
| Term | Meaning in the EU context |
|---|---|
| IVD | A device that meets the definition in Article 2(2) of the IVDR |
| LDT | A commonly used description for a test developed within a laboratory |
| In-house IVD | An IVD manufactured and used within an EU health institution under the conditions of Article 5(5) |
| CE-marked IVD | A device placed on the market following the applicable IVDR conformity assessment route |
A laboratory should not assume that calling a test an LDT makes it exempt. It must first determine whether the product has an IVD intended purpose and then establish whether the health institution and device satisfy every applicable Article 5(5) condition.
Who can use the Article 5(5) exemption?
Article 5(5) is limited to health institutions established in the European Union.
A health institution is an organisation whose primary purpose is the care or treatment of patients or the promotion of public health. Depending on national law and the organisation’s activities, this can include hospitals, medical laboratories and public health institutes.
Not every laboratory automatically qualifies. The organisation must assess:
- whether it meets the IVDR definition of a health institution;
- whether national legislation adds registration, accreditation or reporting requirements;
- which legal entity manufactures and uses the device;
- whether the device remains within that legal entity throughout its lifecycle; and
- whether manufacture takes place on a non-industrial scale.
Member States may restrict the manufacture and use of particular types of in-house devices. National requirements must therefore be checked separately from the EU-level conditions.
Which IVDR Article 5(5) requirements already apply?
| Requirement | Current status in August 2026 |
|---|---|
| Compliance with applicable Annex I general safety and performance requirements | Applicable since 26 May 2022 |
| Device not transferred to another legal entity | Applicable since 26 May 2022 |
| Manufacture and use on a non-industrial scale | Applicable since 26 May 2022 |
| Appropriate quality management system | Applicable since 26 May 2024 |
| Laboratory compliance with EN ISO 15189 or applicable national provisions | Applicable since 26 May 2024 |
| Information supplied to the competent authority upon request | Applicable since 26 May 2024 |
| Public declaration identifying the institution and devices and addressing GSPR compliance | Applicable since 26 May 2024 |
| Article 5(5)(g) documentation for Class D in-house IVDs | Applicable since 26 May 2024 |
| Manufacture according to the applicable documentation | Applicable since 26 May 2024 |
| Review of experience from clinical use and corrective actions | Applicable since 26 May 2024 |
| Justification that an equivalent device cannot meet the target patient group’s specific needs | Applicable from 26 May 2028 |
The 2028 deferral concerns Article 5(5)(d). It does not postpone the other applicable requirements.
What MDCG 2023-1 clarifies
Manufacture and use must remain within the same legal entity
The in-house device cannot be transferred to another legal entity. Physical location alone does not determine compliance. Several hospitals may belong to one legal entity, while different organisations operating within one hospital may be separate legal entities.
The legal and organisational structure should therefore be documented before relying on the exemption.
Patient specimens, protocols and test results are not themselves devices and may be shared under the conditions described in MDCG 2023-1. However, the in-house device must remain manufactured and used within the health institution that is relying on Article 5(5).
Modifying or combining products may create an in-house device
Manufacture is not limited to producing a test entirely from raw materials. MDCG 2023-1 explains that it can include:
- manufacturing from raw materials, parts or components;
- combining products in a way that creates a new device;
- modifying an existing device to create a new device; and
- assigning an IVD intended purpose to an RUO product for use within the health institution.
A laboratory should therefore assess modified commercial tests, laboratory-developed software, custom PCR mixtures and RUO-based diagnostic workflows rather than limiting its inventory to assays developed completely in-house.
High testing volume does not automatically mean industrial-scale manufacture
Article 5(5) does not apply to devices manufactured on an industrial scale, but the IVDR does not define a single numerical threshold.
MDCG 2023-1 recommends a case-by-case assessment considering production volume, commercial aspects and the manufacturing process. For IVDs, analysing a large number of patient specimens does not automatically mean that the device has been manufactured on an industrial scale.
The institution should nevertheless be able to explain why the scale of manufacture reflects the estimated clinical need rather than an industrial or commercial production model.
Why ISO 15189 is not enough on its own
ISO 15189:2022 specifies requirements for quality and competence in medical laboratories and now expressly covers point-of-care testing.
For Article 5(5), the laboratory must comply with EN ISO 15189 or applicable national provisions, including national provisions concerning accreditation. MDCG 2023-1 explains that compliance may be demonstrated through accreditation or other means, unless national law requires accreditation.
However, ISO 15189 does not fully cover the manufacture of an in-house IVD or every applicable Annex I requirement. The QMS should also address areas such as:
- device and intended-purpose control;
- risk management throughout the device lifecycle;
- design and manufacturing controls;
- supplier and material controls;
- performance evidence;
- traceability and device identification;
- monitoring of clinical experience;
- incidents, complaints and corrective actions;
- document control; and
- communication with competent authorities.
Elements from standards such as ISO 13485 and ISO 14971 may help address these areas. They should be selected according to the device, risk, QMS gaps and applicable national requirements rather than presented as automatically mandatory in every case.
Public declaration and GSPR evidence
Since 26 May 2024, the health institution must make a declaration publicly available that includes:
- its name and address;
- the details needed to identify the in-house devices;
- confirmation that the devices meet the applicable Annex I general safety and performance requirements; and
- a reasoned justification for any applicable GSPR that is not fully met.
Annex A of MDCG 2023-1 provides a proposed declaration format. Health institutions should also check whether national rules specify the language, format, publication method or notification process.
The declaration should be supported by evidence. It is not a substitute for a documented GSPR assessment, risk management, performance evidence or device controls.
Documentation for Class D and other in-house IVDs
Article 5(5)(g) requires more detailed documentation for Class D in-house IVDs. It must make it possible to understand the manufacturing facility, manufacturing process, design and performance data, including the intended purpose, and allow the competent authority to assess compliance with Annex I.
MDCG 2023-1 indicates that Annex II of the IVDR can be used as guidance when organising this information.
Member States may extend documentation requirements to Class A, B or C in-house IVDs. Even when Article 5(5)(g) does not impose the same documentation scope, every in-house device still needs sufficient evidence to support its applicable GSPR compliance, QMS controls and safe use.
Preparing the 2028 justification of non-equivalence
From 26 May 2028, the health institution must document why the specific needs of its target patient group cannot be met, or cannot be met at the appropriate level of performance, by an equivalent device available on the market.
MDCG 2023-1 recommends considering technical, biological and clinical factors. Examples can include:
- a different intended purpose;
- a specific patient population;
- specimen types not covered by available alternatives;
- different clinical conditions or use environments;
- a required level of sensitivity or other critical performance characteristic;
- a different principle of operation; or
- a clinically relevant combination of markers or results.
Price or institutional preference alone is unlikely to demonstrate that a target patient group’s specific needs cannot be met.
The market assessment should be reproducible and reviewed regularly. If a suitable CE-marked equivalent later becomes available, the institution should update the assessment and consider a controlled transition where the equivalent device meets the relevant clinical need.
Does Article 5(5) apply to non-EU laboratories?
No. The health institution exemption is limited to health institutions established in the European Union.
MDCG 2023-1 also notes that Article 6(2) applies where diagnostic services are offered through distance sales to patients in the Union. A non-EU laboratory should not assume that CLIA or CAP accreditation, or the fact that a test is used within one laboratory, creates an Article 5(5) exemption.
The applicable IVDR pathway depends on the service model, the device, the location of the laboratory, the recipient of the service and how the result is supplied. This should be assessed before testing EU patient specimens or offering diagnostic services into the Union.
Frequently asked questions
An in-house IVD does not follow the normal CE-marking route when the health institution and device satisfy all applicable conditions of Article 5(5). Relevant Annex I requirements and the Article 5(5) conditions still apply.
If those conditions are not met, the institution cannot rely on the exemption and another compliant regulatory pathway is required.
Not through the normal conformity assessment route. Oversight of in-house devices is primarily exercised by national competent authorities, which can request information, inspect activities and impose national requirements.
The IVDR requires the laboratory to comply with EN ISO 15189 or applicable national provisions, including national provisions on accreditation. MDCG 2023-1 recognises that ISO 15189 compliance may be demonstrated through accreditation or other means. National law may nevertheless make accreditation mandatory.
Only if the receiving location is part of the same health institution and legal entity and the other Article 5(5) conditions remain satisfied. Organisations should confirm their national legal structure rather than assuming that hospitals within the same network form one legal entity.
MDCG 2023-1 distinguishes the device from the patient specimen. Samples can be sent to the health institution for analysis, provided the in-house device itself remains manufactured and used within the qualifying health institution and legal entity.
Article 5(5)(d) becomes applicable. Health institutions relying on the exemption must be able to document why an equivalent device available on the market cannot meet the target patient group’s specific needs, or cannot meet them at the appropriate level of performance.
Preparing for Article 5(5) compliance
Health institutions should maintain a controlled inventory of in-house IVDs, confirm eligibility under Article 5(5), assess applicable GSPRs, strengthen their QMS, publish the required declaration and prepare for competent-authority review.
The 2028 non-equivalence requirement should also be prepared in advance because it requires a structured market assessment and device-specific clinical, technical or biological justification.
For an operational implementation sequence, use MDx CRO’s IVDR laboratory readiness checklist.
MDx CRO supports EU and non-EU laboratories with Article 5(5) assessments, QMS gap analysis, GSPR documentation, in-house IVD evidence and cross-border regulatory strategy. Explore our laboratory compliance services.
