Human Subjects Research Overview

The Health and Human Services Policy for Protection of Human Research Subjects in 45 CFR Part 46 defines a human subject as a living person about whom an investigator obtains either 1) data through intervening or interacting with the person or 2) identifiable private information. Federal requirements to protect human subjects may apply to research on human specimens (such as cells, blood, and urine), residual diagnostic specimens, and medical information. Research involving existing data, documents, records, pathological specimens, diagnostic specimens, or tissues that are individually identifiable is considered “research involving human subjects.”

Key definitions:

  • Intervention includes both physical procedures by which data are gathered (for example, venipuncture) and manipulations of the subject or the subject's environment that are performed for research purposes. Interaction includes communication or interpersonal contact between investigator and subject.
  • Individually identifiable: The identity of the subject is or may readily be ascertained by the investigator or associated with the information. Private information must be individually identifiable in order for obtaining the information to constitute research involving human subjects.
  • Private information includes information about behavior that occurs in a context in which an individual can reasonably expect that no observation or recording is taking place, and information which has been provided for specific  purposes by an individual and which the individual can reasonably expect will not be made public (for example, a medical record).
View NIH Decision Tree

Your research may fall under the umbrella of human subjects research even if you aren't working on humans directly. For example, some basic research on biological samples would be considered human subjects research, even if they were collected for a different study. The NIH offers a decision tree (see example)  to make the determination of whether the NIH will consider proposed research to be human subjects research. If you have questions about whether your application involves human subjects, consult your NIH Program Official or ask your institutional review board (IRB) or independent ethics committee (IEC) before writing your application.

If you're using coded private information, data, or specimens, NIH will consider your research to involve human subjects unless it meets both of the following conditions:

  • You are not collecting samples by interacting or intervening with living people.
  • None of the investigators or collaborators/co-authors can identify the subjects through coded private information or specimens (e.g., an investigator's access to identity is prohibited by a written agreement).

If any investigator involved in the research can determine a subject's identity or has access to identifiers, the research is considered to involve human subjects and human subjects requirements apply.

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Last Reviewed on
February 2018