Protected health information
Also called: PHI
Individually identifiable health information held or transmitted by a covered entity or business associate, in any form.
The identifiable part matters more than the clinical part. A list of names that reveals those people are patients of a particular practice is protected health information even with no diagnosis attached, which is why a customer list in an accounting package or a segment in a marketing tool can be a problem.
Source: 45 CFR 160.103
See also: Covered entity, Business associate, De-identification