Health care organizations could retain their own identifiers for patients, which may not be permanent. Barring cases of injury or illness where the finger, eye, etc. is lost or damaged, biometric identifiers are permanent. Although the SSN is in theory a unique number, there have been cases of more than one person issued the same number. The UHID identifies one, and only one, individual. Health care organizations could retain their own identifiers for patients, which may not be unique.
Biometric identifiers are unique for each individual.
The public does not have access to the Social Security Administration database, which would contain data fields necessary to completely identify the individual. Identifying information may include data items such as name, birth date, sex, address, etc. This information is not incorporated in the UHID but is associated with it by linkages. However, no actual mechanism to support this feature is discussed in the Guide, so it is difficult to gauge how these criteria would be supported. The MPI does not include actual patient information, but pointers to locations where patient data is stored.