The GUID, or Global Unique Identifier, is an alphanumeric code that is created by the NDA GUID Tool and used as an identifier for a research participant. GUIDs are based on basic personally identifiable information (PII) that is typically found on a birth certificate (first name, middle name, last name, date of birth, place of birth, sex at birth, and town/municipality of birth). The principal investigator must strip all PII before submitting any data to the NDA. In fact, GUIDs are required for all submitted data and are created using the GUID Tool, which can be downloaded or requested through creating an NDA User Account. In the event that adequate information is not available to fully create a valid GUID, a pseudoGUID can be created. This can be done in the GUID Tool or you can request a set of pseudoGUIDs through the NDA Help Desk.

Here’s how it works:

1. A member of the research project team enters participant PII into the tool.
2. The tool uses the PII, without it ever leaving your computer, to generate a series of one-way hash codes.
3. The hash codes are encrypted and sent to the GUID system at NDA.
4. If the codes match an existing GUID, this GUID is sent back to the researcher.
5. If they do not, a new one is created and sent back.

Using such a system, the same participant information will return the same GUID whenever or wherever it is entered. This allows NDA to anonymously link participant data records across time and locations, without ever receiving identifying information. The ability to link subject records and the protection of participant confidentiality are both critical components of data sharing.

When enrolling participants in your projects, it is important to keep in mind the information you will need to create NDA GUIDs using you GUID Tool privileges. This includes:

• First Name
• Middle Name
• Last Name
• Sex
• Date of Birth
• City/Municipality of Birth

All this information should be recorded exactly as it appears on the birth certificate, to ensure that it does not change over the course of the participant’s life.

If any of this information is missing, a pseudoGUID can be created using the GUID Tool. This is a random ID that can be used as a placeholder where this information is not available, and "promoted" to a genuine GUID when the information is obtained at a future date. If you are interested, you can find more details on how the NDA GUID Tool works. If you still have any questions, you can always contact the NDA Help Desk.