Can Participants Withdraw Biological Samples After Analyses Have Already Been Performed?

What Does Withdrawal Mean Once a Sample Has Already Been Used?

A participant contributes blood, tissue, DNA, or another biological specimen and later decides that they no longer want it used for research. If the sample is still sitting untouched in a repository, the practical meaning of withdrawal may seem straightforward.

But what if researchers have already consumed part of the specimen, generated sequence data, incorporated measurements into an analysis, distributed portions to another laboratory, or published results? At that point, withdrawal remains meaningful, but it cannot necessarily rewind everything that has already happened.

Withdrawal Can Stop Future Uses, but It Cannot Always Undo Completed Research

Withdrawal Is Usually Prospective Rather Than a Complete Reversal of Research

A participant can stop future participation without necessarily erasing the past

Research ethics recognizes a participant's ability to discontinue participation. Under HHS regulations, participants may discontinue participation without penalty or loss of benefits to which they are otherwise entitled.

For stored biospecimens, HHS advisory guidance states that the right to withdraw extends to withdrawing specimens from future research. The same guidance also explains an important practical boundary: investigators are not generally obligated to retrieve specimens already distributed to secondary users, and analyses already completed will generally not be destroyed or removed from datasets.

Withdrawal therefore often changes what may happen next rather than undoing everything that happened before the request.

A specimen can exist in several places by the time withdrawal occurs

Biological material does not necessarily remain in one freezer. A repository may divide a specimen into aliquots, distribute portions to collaborating laboratories, extract DNA, prepare slides, create cell cultures, or send material to secondary researchers.

A withdrawal request therefore needs to establish what material remains under the repository's control and what has already left it.

HHS guidance specifically recognizes that the obligation to honor a withdrawal request does not extend to retrieving specimens already distributed to secondary users. This practical limitation should be disclosed to participants when future specimen use is initially discussed.

Completed analyses cannot necessarily be “put back” into the specimen

Some laboratory analyses consume or irreversibly alter biological material. Once DNA has been sequenced, tissue stained, cells destroyed in an assay, or a portion of blood consumed, there may be no physical specimen corresponding to that analysis left to withdraw.

More importantly, the analysis may have created a new research resource: data. Sequence files, assay measurements, images, derived variables, and statistical results can continue to exist after the physical material has been destroyed.

This distinction between physical samples and information derived from biological samples becomes crucial when defining what a withdrawal request can still reach.

Already collected research data may sometimes remain in the study

OHRP's guidance on withdrawal from HHS-conducted or supported research states that investigators may retain and analyze already collected data relating to a participant who withdraws, provided the analysis remains within the scope of the IRB-approved protocol. The guidance applies even when those data include identifiable private information.

OHRP also notes that, for research outside certain FDA requirements, investigators may choose to honor a participant's request to destroy or exclude already collected data. That possibility should not be confused with a universal obligation to do so.

Other regulatory systems can impose different requirements. Researchers should therefore avoid promising complete deletion unless the study can actually deliver it.

FDA-regulated research can impose stronger retention requirements

Withdrawal rules can differ when research is regulated by the U.S. Food and Drug Administration. OHRP's withdrawal guidance notes that FDA guidance requires data collected before withdrawal in FDA-regulated clinical trials to remain in the trial database in order to preserve the study's scientific validity.

This is a useful illustration of a broader point: the ethical right to discontinue future participation does not necessarily imply a right to remove every previously collected research record from every type of study.

Revoking health-information authorization may also have prospective limits

Under the U.S. HIPAA Privacy Rule, as summarized by OHRP, an individual can revoke an authorization in writing, except to the extent that a covered entity has already acted in reliance on it. Information already disclosed under a valid authorization does not necessarily have to be retrieved.

Again, the general pattern is prospective. Withdrawal can stop or restrict future activity without necessarily reversing actions that were lawful when they occurred.

De-identifying a sample after withdrawal is not an ethical loophole

Suppose a participant asks to withdraw an identifiable stored specimen. The repository could technically remove all identifiers and codes, making it impossible to reconnect the sample to that individual. Could it do this instead of destroying or withdrawing the specimen, then continue using it?

HHS advisory guidance treats that maneuver cautiously. It states that permanently stripping identifiers after a withdrawal request merely to avoid honoring the request would be ethically suspect and could violate the principle of respect for persons or the original consent terms.

The guidance similarly warns against responding to withdrawal of broad consent by de-identifying the participant's material solely so that research use can continue. If such a consequence of withdrawal is contemplated, it should have been clearly disclosed beforehand, and even then an IRB may regard the arrangement as ethically problematic.

Published findings usually cannot be retracted merely because one donor withdraws

Once individual measurements have contributed to aggregate analyses, figures, statistical models, or publications, extracting one person's contribution may be impossible or scientifically inappropriate. Published knowledge cannot ordinarily be made nonexistent.

This does not mean that withdrawal is meaningless. It means that withdrawal affects future use of identifiable, retrievable materials differently from findings already incorporated into completed research.

Withdrawal should be granular when the research arrangement allows it

A participant may want to stop new specimen use but permit researchers to retain previously generated data. Another may want remaining specimens destroyed but accept that already shared material cannot be recovered. Some repositories may offer several withdrawal options, while others use a simpler model.

Whatever system is adopted, participants should receive a clear explanation of the options and their limits. A statement that participants may “withdraw at any time” is incomplete if it creates the impression that years of completed research can necessarily be erased on request.

The repository needs traceability to make withdrawal meaningful

If specimens remain identifiable or coded, a repository needs sufficient records to locate material subject to a valid withdrawal request. This creates an interesting governance tension: preserving the ability to honor withdrawal may require retaining a controlled connection between the donor and stored material.

Once material has been irreversibly anonymized, individual withdrawal may become technically impossible because nobody can determine which specimen belongs to the withdrawing person.

That consequence should be considered when designing the repository rather than discovered during the first withdrawal request.

A Participant Withdraws After Part of the Sample Has Already Been Sequenced

Common Misunderstandings About Withdrawing Stored Samples

Define Withdrawal Before the First Specimen Enters Storage

If you are building or managing a repository, specify what withdrawal means operationally. If you are using stored samples, check those terms before assuming that all retained material remains available.

When a Participant Withdraws a Biological Sample

Frequently Asked Questions About Withdrawing Biological Samples

Withdrawal Can Stop the Future Without Necessarily Erasing the Past

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