ICF (Informed Consent Form)

An Informed Consent Form (ICF) is the specific written document a prospective research participant (or their legally authorized representative) reads and signs before enrolling in a study. It is not the same thing as “informed consent” itself, which is the underlying disclosure-comprehension-voluntariness process regulated separately under informed consent and covered in full in CASRAI’s Informed Consent in Research guide. This entry focuses on the ICF as an artifact: what it must contain, who has to approve it before it can be used, how its versions are tracked, and how it changes for participants who don’t read English.

Operational definition

A document counts as an ICF when it is a written instrument, reviewed and approved by an Institutional Review Board (IRB) or equivalent ethics committee before use, that restates the required disclosure elements in a form intended to be given to (and, ordinarily, signed by) the prospective participant. For US federally funded or federally regulated research, “required disclosure elements” means the basic and additional elements set out in 45 CFR 46.116(b)-(c) (the Common Rule) and, for FDA-regulated clinical investigations of drugs, biologics, or devices, the closely parallel basic and additional elements in 21 CFR 50.25. Basic elements common to both include: the research purpose, expected duration, and procedures, including identification of any experimental procedures; foreseeable risks and discomforts; reasonably expected benefits; disclosure of appropriate alternative procedures or treatments; confidentiality protections; for research involving more than minimal risk, an explanation of whether compensation or medical treatment is available if injury occurs; contacts for questions about the research, participants’ rights, and research-related injury; and a statement that participation is voluntary, with refusal or withdrawal involving no penalty or loss of benefits. The 2018 revised Common Rule additionally requires a concise “key information” summary at the start of the document.

Documentation of consent is governed separately from the consent process itself — 45 CFR 46.117 (Common Rule) and, for FDA-regulated research, 21 CFR 50.27 — which is why an ICF can exist as a compliant document even in edge cases (e.g., the short-form pathway below) that don’t look like a conventional single long-form document.

IRB approval and version control

An ICF is only valid for use once the IRB has approved that specific version. Because a study’s consent document is commonly revised over its lifecycle (protocol amendments, new safety information, updated risks), OHRP guidance recommends IRBs use a method — a date stamp, version number, or initialed/dated approval — that lets staff and monitors immediately identify the current IRB-approved version and distinguish it from superseded drafts. In practice this is almost always an IRB approval stamp physically or electronically applied to the document, showing the approval date and, where the IRB uses time-limited approvals, an expiration date; federal regulations make no provision for a grace period to keep using a form, or continuing a study, past that expiration date. Version history and re-approval of each ICF revision are checked during a monitor’s source document review and are a standard item in an audit or FDA inspection.

Readability

The Common Rule and FDA regulations both require that information be conveyed “in language understandable to the subject,” but neither sets a numeric reading-level threshold. IRBs and institutional guidance commonly operationalize that requirement as a target reading level of roughly 6th-8th grade (measured with a tool such as Flesch-Kincaid), plain-language rewriting of clinical and statistical jargon, and short sentences and lay headings in place of dense legal-style paragraphs. This is institutional/IRB practice built on top of the regulatory “understandable language” standard, not a separate codified requirement.

Short-form ICF for non-English-speaking participants

Where a prospective participant does not speak English and a fully translated long-form ICF isn’t available, 45 CFR 46.117(b)(2) (and the parallel 21 CFR 50.27(b)(2) for FDA-regulated research) permits a short-form written consent document instead. The short form states, in a language understandable to the participant, that the required elements of consent have been presented orally; the full English-language document serves as the written summary of what was presented. A witness fluent in both languages (who may also be the interpreter, provided they are not otherwise affiliated with the study team as an investigator) must be present for the oral presentation. The subject or their representative signs the short form itself; the person obtaining consent signs the English summary; and the witness signs both. This is a distinct, IRB-approved regulatory pathway — not an informal workaround — and institutions typically maintain pre-approved short forms in the languages most common among their participant populations.

Examples

• A full-length English-language ICF for a Phase 3 drug trial: multiple pages restating the 21 CFR 50.25 elements, carrying an IRB approval stamp with approval and expiration dates and a version number in the footer, provided to each participant for review and signature before any study procedures begin.
• A short-form ICF used for a participant who speaks only Spanish, where no translated long-form document exists yet: the short form (in Spanish) states that the required elements were presented orally; a bilingual witness signs both the short form and the English-language summary alongside the person obtaining consent.

Counter-example

A verbal consent script read aloud to a participant, with no accompanying document for the participant to sign, where the IRB has waived the documentation requirement under 46.117(c) for minimal-risk research. The underlying informed-consent process under 46.116 still has to occur and still has to meet every substantive disclosure requirement — but because no written instrument is produced or retained, there is no ICF in this scenario, only a documented waiver of the form requirement.

Related terms and further reading

• Informed consent — the broader ethical/regulatory concept and disclosure process the ICF documents.
• Informed Consent in Research: What It Requires and How It Works — full guide to the consent process, waivers, and vulnerable-population protections.
• IRB (Institutional Review Board) — the body that reviews and approves every ICF version before use.
• Human Research Participant (Human Subject)
• Vulnerable Populations in Research