⚠️ January 2025 HIPAA Security Rule Updates Now in Effect

What is PHI? Definition & Examples

Comprehensive guide to Protected Health Information under HIPAA. Learn the definition, 18 identifiers, real-world examples, and how to properly identify and protect health data.

What is Protected Health Information (PHI)?

Protected Health Information (PHI) is any information in a medical record or designated record set that can be used to identify an individual and that was created, used, or disclosed in the course of providing a healthcare service such as diagnosis or treatment.

The Three-Part Test for PHI

Information is PHI if it meets ALL three criteria:

  1. Identifies an individual (or could reasonably be used to identify an individual)
  2. Relates to health condition, healthcare provision, or payment for healthcare
  3. Created or held by a covered entity or business associate

PHI includes obvious things like medical records and test results, but also extends to billing information, email or phone conversations about patients, appointment schedules, and even photographs that could identify individuals in a healthcare context.

The 18 HIPAA Identifiers

HIPAA specifies 18 types of identifiers that, when combined with health information, create Protected Health Information that must be protected.

Names

Full name, maiden name, aliases

Geographic Subdivisions

Street address, city, county, zip code (first 3 digits OK if > 20,000 people)

Dates

Birth date, admission date, discharge date, death date, dates of service (except year)

Telephone Numbers

Home, work, mobile phone numbers

Email Addresses

Any email address associated with the individual

Social Security Numbers

Full or partial SSN

Medical Record Numbers

MRN, patient ID, account numbers

Health Plan Beneficiary Numbers

Insurance member ID, policy numbers

Account Numbers

Bank account, credit card numbers

Certificate/License Numbers

Driver's license, professional licenses

Vehicle Identifiers

License plate numbers, VIN, serial numbers

Device Identifiers

Medical device serial numbers, MAC addresses, IP addresses

Web URLs

Website addresses associated with individual

Biometric Identifiers

Fingerprints, voiceprints, retinal scans, facial photos

Full-Face Photos

Any photographic images showing the face

Other Unique Numbers

Any other unique identifying number, code, or characteristic

Important Note

Even if you remove most identifiers, information may still be considered PHI if there's any reasonable basis to believe it could be used to identify an individual. For full de-identification, you must remove ALL 18 identifiers (Safe Harbor method) or have an expert certify low re-identification risk.

Examples of Protected Health Information

Medical Records
  • Patient chart containing name and diagnosis
  • Lab results with patient identifier
  • Prescription with patient name and medication
  • Surgical notes with patient information
  • Radiology images with patient name in DICOM data
Billing & Insurance
  • Invoice showing patient name and services rendered
  • Insurance claim with member ID and treatment codes
  • Explanation of Benefits (EOB) statement
  • Payment records linked to patient accounts
  • Prior authorization requests with patient details
Communications
  • Email discussing specific patient's condition
  • Voicemail about patient appointment or results
  • Text message containing patient health information
  • Fax transmission of medical records
  • Patient portal messages about health status
Administrative
  • Appointment schedule showing patient names
  • Sign-in sheet at reception desk
  • Patient registration forms
  • Authorization forms with patient signatures
  • Medical histories with identifying information

What is NOT Protected Health Information

Understanding what doesn't qualify as PHI is equally important for avoiding over-protection that impedes normal business operations.

De-identified Data
  • Statistical report: '45% of patients improved' (no identifiers)
  • Age ranges instead of exact dates: 'Male, 40-45 years old'
  • General location: 'Patients from California' (no specific address)
  • Diagnosis codes without patient identifiers
  • Anonymized research data with all 18 identifiers removed
Educational/Reference Materials
  • General medical textbooks and journals
  • Treatment protocols and clinical guidelines
  • Health education brochures
  • Generic anatomy diagrams
  • Medical terminology reference materials
Employment Records
  • Employee personnel files (unless healthcare provider employee)
  • Workers' compensation records held by employer (not provider)
  • Occupational health records not held by covered entity
  • General HR records unrelated to health benefits
Consumer Wellness Data
  • Fitness tracker data not shared with healthcare provider
  • Consumer health app data collected directly from user
  • Self-reported symptoms in non-clinical app
  • Nutrition tracking app data (direct-to-consumer)
  • Meditation or mental wellness app data (not clinical)

Key Distinction: The critical factor is whether information identifies or could identify a specific individual. Anonymous or properly de-identified data is not PHI, but be cautious—small data sets can often be re-identified even when obvious identifiers are removed.

Three Forms of PHI and How to Protect Each

Paper PHI

Protected health information in physical form

Required Protections:

  • Store in locked cabinets or secure rooms
  • Implement clean desk policies
  • Use shredding for disposal (not regular trash)
  • Limit access to authorized personnel only
  • Track document movement with logs
Electronic PHI (ePHI)

Protected health information in electronic format, subject to Security Rule

Required Protections:

  • Encrypt data at rest and in transit
  • Implement access controls and unique user IDs
  • Maintain audit logs of all access
  • Use firewalls and intrusion detection
  • Secure backup and disaster recovery
Oral PHI

Spoken protected health information, often overlooked but still protected

Required Protections:

  • Avoid discussing patients in public areas
  • Use private rooms for sensitive conversations
  • Lower voices when discussing PHI
  • Implement 'cone of silence' policies in open offices
  • Be mindful of phone conversations in shared spaces

Common PHI Questions & Scenarios

Can I text a patient their appointment time?
Medium Risk

It depends. If the text contains only the appointment time without health information, it's generally acceptable. However, including reason for visit, treatment details, or test results would be PHI requiring encryption or patient consent. Best practice: use secure patient portal messaging.

Is a waiting room sign-in sheet with names PHI?
Low Risk

Yes. Names combined with the fact that someone is at a healthcare facility creates PHI. Consider alternatives like giving patients numbers or having them notify staff verbally rather than signing in publicly.

Can I email PHI to another provider for consultation?
High Risk

Only with appropriate safeguards. Regular email is not secure. You should use encrypted email, a secure portal, or ensure you have patient authorization. The receiving provider must also be authorized to receive the information.

Are voice-to-text transcription services HIPAA compliant?
High Risk

Only if the service provider signs a Business Associate Agreement and encrypts the data. Services like standard Siri, Google Assistant, or Alexa are NOT HIPAA compliant. Use healthcare-specific dictation services with BAAs.

Can I discuss patient cases with colleagues in the cafeteria?
High Risk

Only if you don't use identifying information. Discussing 'a 45-year-old diabetic patient' without names, locations, or other identifiers for educational purposes may be permissible. However, naming patients or providing enough detail to identify them violates HIPAA.

Is aggregate data like '30% of our patients have diabetes' PHI?
Low Risk

No, if properly aggregated and anonymized. Statistical data that doesn't identify individuals is not PHI. However, small populations can still risk re-identification (e.g., 'the only pediatric cardiac patient we saw last year').

De-identification: Making PHI Not PHI

De-identification removes PHI status from health information, allowing it to be used more freely for research, analysis, and other purposes. HIPAA recognizes three approaches:

Safe Harbor Method

Remove all 18 HIPAA identifiers and have no actual knowledge that residual information could identify individuals

Advantages:

Clear standard, relatively straightforward to implement

Limitations:

Removes significant utility from data, may be overly restrictive

Expert Determination

Have a qualified expert apply statistical or scientific principles to determine re-identification risk is very small

Advantages:

Retains more data utility, allows for more nuanced approach

Limitations:

Requires expert statistician, more expensive, documentation intensive

Limited Data Set

Remove most identifiers but retain dates, city, state, zip, and ages. Requires Data Use Agreement

Advantages:

More useful for research, still provides significant protection

Limitations:

Not fully de-identified, requires DUA, still has some restrictions

Warning: Re-identification Risk

Research has shown that even "de-identified" data can often be re-identified by combining it with other publicly available datasets. The famous Netflix Prize incident demonstrated that supposedly anonymous viewing data could identify individuals. When in doubt, consult with a privacy expert or statistician.

Key Takeaways About PHI

  • PHI is broader than you think. It includes not just medical records but billing info, appointment schedules, even the fact that someone is a patient.
  • All three forms of PHI must be protected. Don't forget about oral PHI and paper PHI in your focus on electronic security.
  • Remove ALL 18 identifiers for Safe Harbor. Partial de-identification doesn't count. Either remove everything or use expert determination.
  • Context matters for PHI status. The same information may or may not be PHI depending on who holds it and how it was obtained.
  • When in doubt, treat it as PHI. Over-protection is safer than under-protection. You can always consult privacy counsel for edge cases.
  • Train your workforce on PHI identification. Many HIPAA violations occur because staff don't recognize what information is protected.

Protecting PHI Starts with Understanding It

Now that you understand what PHI is, assess whether your organization is properly protecting it under HIPAA requirements.