 The Global Unique Identifier (GUID) is a subject identification (ID) allowing researchers to share specific data about a study participant without exposing personally identifiable information (PII) and to match participants across labs and research data repositories. GUIDs are required for all submitted data and are created using the GUID Tool which can be requested through an NDA account. GUIDs are based on basic information typically found on a birth certificate (first name, last name, date of birth, sex at birth and city/municipality of birth) and can be generated either individually or through a batch process using the template available in the GUID Tool. 