Instructions for Use (IFU) for Medical Devices: What FDA Labeling Rules Expect

This page describes products and general use; it is not medical advice.

Clinic staff, buyers and students who search for “instructions for use” on a medical device usually need to know three things: what counts as the instructions under US rules, what the labeling regulation expects, and why some devices ship without directions. In US law the phrase “instructions for use” (IFU) is not a defined term. The rules speak of labeling and of adequate directions for use, and the IFU is the part of the labeling that carries those directions.

What an IFU is and where it sits in FDA labeling

An IFU is the written or printed direction sheet, booklet or insert that accompanies a device. The FDA’s device labeling overview separates two terms. A label is the display of written, printed or graphic matter on the immediate container of the device, and the same information must appear on the outside container or be legible through it. Labeling is broader: written, printed or graphic matter on the device or its containers, or accompanying the device. The FDA reads “accompanying” liberally and names instruction books, direction sheets, pamphlets and brochures as examples. That is where an IFU belongs.

The general device labeling regulation is 21 CFR Part 801. Related parts cover in vitro diagnostic products (Part 809), investigational devices (Part 812), unique device identification (Part 830) and the quality system regulation (Part 820). Symbols on labels are addressed in 21 CFR 801.15 (see medical device labeling symbols and ISO 15223-1), and natural rubber latex user labeling in 21 CFR 801.437 (see not made with natural rubber latex).

What “adequate directions for use” means (21 CFR 801.5)

21 CFR 801.5 defines “adequate directions for use” as directions under which the layman can use a device safely and for the purposes for which it is intended. Intended use itself is defined in 21 CFR 801.4. The test is the layperson standard: unless an exemption applies, the directions on or with the device must let an ordinary user operate it safely for its stated purpose.

When directions for use are exempt (table)

The FDA publishes a page on exemptions from adequate directions for use. These are the rows it lists, with what each requires instead.

Section	Exemption	What still applies
801.109	Prescription devices	Rx statement; labeling with information for use, hazards and precautions; issue or revision date on labeling other than labels and cartons
801.110	Retail exemption: device delivered by a licensed practitioner or dispensed on prescription	Practitioner name and address, directions for use, required cautionary statements
801.116	Commonly known directions	Applies where the common uses are understood by the ordinary person
801.119	In vitro diagnostic products	Exempt if the labeling meets 21 CFR 809.10
801.122	Manufacturing use	Label carries “Caution: For manufacturing, processing, or repacking”
801.125	Teaching, research, law enforcement, chemical or physical testing	Exemption for devices used in those settings
801.127	Expiry of exemptions	Exemptions lapse if the devices go to non-exempt persons or are used for other purposes

An exemption from layperson directions does not mean a device has no labeling. It means a different set of labeling requirements applies.

What prescription-device labeling must show (21 CFR 801.109)

For a prescription device the label bears “Rx only” or “℞ only”, or the statement “Caution: Federal law restricts this device to sale by or on the order of a ___”, with the blank filled by physician, dentist, veterinarian or another state-licensed practitioner. The label also states the method of application or use. Under 801.109(e), all labeling bearing information for use of the device, except labels and cartons, must carry the date of issuance or of the latest revision. See the Rx only symbol for the statement itself.

Medical device labeling requirements: Part 801 at a glance

Part 801 is the minimum labeling regulation for all devices. For a buyer, the practical reading is that labeling is three layers: the label on the immediate container, the outer carton, and accompanying material such as the IFU. Identification elements sit alongside: the unique device identifier, the lot number and the date of manufacture symbol.

How to read an IFU before use

• Check the issue or revision date on the IFU. For prescription devices the regulation requires one on labeling other than labels and cartons.
• Confirm the stated intended use matches how the device will be used; intended use is the basis of the directions.
• Look for the Rx statement and any cautionary statements the regulation requires.
• The FDA treats accompanying direction sheets as part of the labeling, so the IFU belongs with the device or its packaging.

Frequently asked questions

What are instructions for use on a medical device?

They are the direction sheet, booklet or insert that accompanies a device and forms part of its labeling. US regulations do not define “IFU” as a term; they require adequate directions for use, meaning directions a layperson can follow safely (21 CFR 801.5).

What are the medical device labeling requirements?

21 CFR Part 801 sets the general requirements, with Part 809 for in vitro diagnostics. Specific sections cover symbols (801.15), prescription devices (801.109) and natural rubber latex (801.437).

Can a device be sold without directions for use?

Yes, in listed cases such as prescription devices, devices with commonly known uses, in vitro diagnostics and devices for manufacturing, teaching or research, each with the conditions in the table above.

Sources

• FDA, Device Labeling, checked 2026-10-30.
• FDA, Labeling Requirements: Exemptions from Adequate Directions for Use, checked 2026-10-30.
• eCFR, 21 CFR 801.5, checked 2026-10-30.
• Cornell LII, 21 CFR 801.109, checked 2026-10-30.