Which of the following is considered an identifier of protected health information?

In the context of protected health information (PHI), an identifier is any piece of information that can be used to identify an individual. While admission dates can be relevant in a healthcare setting, they are not inherently considered as identifiers of PHI. Protected health information typically includes data that not only relates to an individual's health condition or treatment but also any specific identifiers that could be connected to a person's identity.

In contrast, social security numbers, health insurance policy numbers, and contact information are all explicit identifiers. They can directly point to an individual and are therefore categorized under PHI. Specifically, social security numbers are unique to individuals and often used for identification purposes. Similarly, health insurance policy numbers are linked directly to insurance plans and can identify a person. Contact information, such as a phone number or email address, also clearly identifies an individual.

Recognizing what constitutes PHI is crucial for maintaining patient privacy and confidentiality as mandated by laws such as the Health Insurance Portability and Accountability Act (HIPAA).