The Health Info identity type is designed to search for a SSN along with a MRN (Medical Records Number) which is entered as a regular expression. If you do not enter a MRN then it would only be searching for a SSN which you could do by just enabling the SSN AnyFind. You can also require DEA Number, NPI Number or a Dictionary match to be found.
This can also be configured from within Policy in the following section of the Policy Settings:
The details of each setting that can be viewed when editing a setting is the help for that setting.
The Identity Finder Settings Viewer is a stand-alone reference tool that describes all of the settings available for the client applications: