IFUInstruction For Use

An Instruction for Use (IFU) is the manufacturer-supplied information that tells the user how to use the device safely, effectively and within the indications the device was approved for. It is one of three forms of 'information supplied with the device' under ISO 20417 — the others are the label on the device itself and the label on its packaging — and it carries the deepest content load of the three.

What an IFU is not: a marketing brochure, a quick-start card by itself, or a translation of a foreign-language master. The IFU is a controlled document, a design output, and a regulated piece of the conformity-assessment dossier. EU MDR Annex I §23 lists 22 mandatory content elements for a device IFU; IVDR Annex I §20 lists a parallel set for IVDs; FDA 21 CFR 801 codifies the US equivalent. None of these is optional and none can be moved to a website without meeting the strict eIFU conditions (EU Regulation 2021/2226) that govern electronic IFUs.

The 22 elements of EU MDR Annex I §23.4 are the most prescriptive reference and a useful master list — IVDR, FDA labelling and ISO 20417 share most of them and add a few of their own. A defensible IFU template builds from this list, maps each section to the underlying regulation, and ties each section to a design output in the DHF.

The table is partial — the regulation enumerates more — but it captures the elements that recur most often in notified-body deficiency letters. The single most cited deficiency is mismatch between the intended purpose stated in the IFU and the intended purpose stated in the technical file.

In a 21 CFR 820 / ISO 13485 design-controls flow, the IFU is a design output. It is generated to satisfy user needs (the user must be able to operate the device safely) and design inputs (the indications and contraindications agreed in the design plan), and it traces forward to design verification (the IFU was reviewed for completeness and accuracy) and design validation (real users could follow it under realistic conditions).

Treating the IFU as a design output has two consequences. First, every revision is a design change and triggers the change-control loop in §4.4 and §7.3.9. Second, the IFU cannot be 'finalised' by Marketing alone — Regulatory, Risk, Human Factors and Clinical all have signing roles in the design-output review.

IEC 62366-1 frames the IFU as one of the risk-control measures available to the manufacturer — but the standard is explicit that warnings in the IFU are the lowest-priority risk control, below 'design the hazard out' and 'add a protective measure that does not rely on the user.' That priority drives a real consequence in the IFU: if a hazard could have been eliminated by design and the manufacturer chose to handle it with an IFU warning instead, the notified body will challenge the justification.

The usability file (UE file under IEC 62366-1) contains the use-specification, the identification of hazardous use scenarios, the formative evaluations that iterated the IFU drafts, and the summative validation that tested the final IFU with representative users under realistic conditions. The IFU revision shipped with the device is the one that passed the summative — not a later revision unless the summative was repeated.

EU MDR Article 10(11) requires the IFU to be supplied in the official language(s) of the Member State where the device is placed on the market. For most devices that means 24 EU languages plus Norwegian and Icelandic for the EEA, and additional languages for Switzerland and the UK. Each translation is a controlled document and must be verified against the source language by a competent translator, with a translation-verification record in the DHF.

A common notified-body finding is divergence between language versions where a late update to the source IFU is not propagated to every translation. The control is to treat the IFU as a single document with multiple language versions under one revision number; any edit to any version forces a re-issue of all.

EU Regulation 2021/2226 sets the conditions under which a manufacturer can ship the IFU in electronic form instead of paper. eIFUs are allowed for active implantable devices, implantable devices and devices for use exclusively by professional users — not for devices used by patients or lay users. The eIFU must be available on a dedicated website, in PDF form, in every required language, for the lifetime of the device plus an additional period (the regulation defaults to two years, manufacturer's choice can be longer).

Additional conditions include: a paper IFU must be supplied free of charge within seven days on request; the website must be available, including in offline form, with appropriate cybersecurity controls; and the manufacturer's quality system must include a procedure for managing eIFU revisions. FDA equivalent rules under 21 CFR 801.109(c) and the related guidance differ in detail but converge on the same principles.

The UDI is the link between the IFU and the regulatory database. Every IFU revision points to a UDI-DI; substantive changes to the IFU (changes to indications, warnings, performance claims) require a new UDI-DI and a re-registration in EUDAMED or the FDA GUDID. The UDI on the device label and on the IFU header must match — a mismatch is one of the easier findings for an investigator to catch in five seconds.

Non-substantive changes to the IFU (typo corrections, layout improvements that do not change content) are managed under document control without a new UDI-DI, but the new revision number must still appear on the IFU and propagate to the technical file.

• Intended purpose in the IFU differs from the intended purpose in the technical file or in EUDAMED.
• Indications include language not supported by the clinical evaluation.
• Warnings are written for the device family rather than the specific configuration shipped.
• Residual risks are listed but not linked to the ISO 14971 risk file.
• Reprocessing instructions omit the maximum number of reprocessing cycles validated under ISO 17664.
• Symbols used in the IFU are not from ISO 15223-1, or are used without the explanatory section.
• Manufacturer or EU representative address is out of date.
• Translation drift between language versions on warnings or contraindications.
• eIFU shipped without the paper alternative being available on request.
• Revision history of the IFU does not match the revision history in the technical file.

Post-market activity changes the IFU more often than design changes do. Every adverse-event trend that uncovers a residual risk, every PMS report that identifies a new use-error pattern, every PSUR that re-states the benefit/risk profile, can drive an IFU change — and each change must flow through change control, usability evaluation, translation, regulatory registration and label-print release.

1. PMS or vigilance signal identifies a new risk or a usability issue.
2. Risk-management file (ISO 14971) updated; new risk control assessed against the hierarchy.
3. If the IFU is the chosen risk control: change control opened; IFU draft revised.
4. Usability evaluation per IEC 62366-1: formative review, summative if the change is material.
5. Translation to every required language; review; back-translation where high-risk.
6. Regulatory: new UDI-DI if substantive; EUDAMED / GUDID update; notified-body notification if significant change.
7. Print release: physical IFUs reprinted, electronic IFUs replaced on the eIFU site; old stock recalled or relabelled.
8. DHF and technical file updated; supplier QMS retains the revision history under document control.

In V5 the IFU is a controlled document linked to a UDI-DI, a clinical evaluation, a risk file and a usability file. When any of those changes, V5 opens a change-control on the IFU automatically, routes the draft through the configured reviewer set (Regulatory, Risk, Clinical, Human Factors, Marketing), enforces a translation gate before approval, and posts the approved version to the eIFU surface with the prior version archived under retention.

• Single revision number across all language versions; release gate blocks mismatched shipments.
• Substantive-change detector flags revisions that need a new UDI-DI and database update.
• Usability file linkage — summative validation status is visible at approval.
• eIFU portal with multi-language PDF, offline cache, paper-request workflow and full access log.
• Print release ties to the WMS so old stock is relabelled or quarantined automatically.
• Audit-trail evidence covers every approval, every translation, every reissue, with Part 11 / Annex 11 e-signatures.