HRPP Policy definition: All direct personal identifiers are permanently removed (e.g., from data or specimens), AND no code or key exists to link the materials to their original source(s), AND the remaining information cannot reasonably be used by anyone to identify the source(s). See Data Security Guidelines.
HIPAA-specific definition: all 18 identifiers from the defined HIPAA list have been removed (or certification under Expert Determination Method). The dataset is no longer considered to contain PHI. Under some circumstances a code permitting re-identification may be retained. See Research A-Z page De-identified Data Sets