What is PHI?

The HIPAA Safe Harbor Rule

In the USA, the 18 categories of PHI are enumerated in the HIPAA Privacy Rule. Here is the relevant section (45 CFR 164.514b(2), the so-called safe harbor rule) that defines a set of conditions for establishing that health information is not individually identifiable (i.e., that it is de-identified):

(2)(i) The following identifiers of the individual or of relatives, employers, or household members of the individual, are removed:

• (A) Names;
• (B) All geographic subdivisions smaller than a State, including street address, city, county, precinct, zip code, and their equivalent geocodes, except for the initial three digits of a zip code if, according to the current publicly available data from the Bureau of the Census:
  • (1) The geographic unit formed by combining all zip codes with the same three initial digits contains more than 20,000 people; and
  • (2) The initial three digits of a zip code for all such geographic units containing 20,000 or fewer people is changed to 000.
• (C) All elements of dates (except year) for dates directly related to an individual, including birth date, admission date, discharge date, date of death; and all ages over 89 and all elements of dates (including year) indicative of such age, except that such ages and elements may be aggregated into a single category of age 90 or older;
• (D) Telephone numbers;
• (E) Fax numbers;
• (F) Electronic mail addresses;
• (G) Social security numbers;
• (H) Medical record numbers;
• (I) Health plan beneficiary numbers;
• (J) Account numbers;
• (K) Certificate/license numbers;
• (L) Vehicle identifiers and serial numbers, including license plate numbers;
• (M) Device identifiers and serial numbers;
• (N) Web Universal Resource Locators (URLs);
• (O) Internet Protocol (IP) address numbers;
• (P) Biometric identifiers, including finger and voice prints;
• (Q) Full face photographic images and any comparable images; and
• (R) Any other unique identifying number, characteristic, or code, except as permitted by paragraph (c) of this section; and

(ii) The covered entity does not have actual knowledge that the information could be used alone or in combination with other information to identify an individual who is a subject of the information.

The final point (R) above refers to paragraph (c), which immediately follows the text quoted above and is reproduced below:

(c) Implementation specifications: reidentification. A covered entity may assign a code or other means of record identification to allow information deidentified under this section to be reidentified by the covered entity, provided that:

• (1) Derivation. The code or other means of record identification is not derived from or related to information about the individual and is not otherwise capable of being translated so as to identify the individual; and
• (2) Security. The covered entity does not use or disclose the code or other means of record identification for any other purpose, and does not disclose the mechanism for re-identification.

The definition of a covered entity is complex, and interested readers are referred to the full text of the HIPAA Privacy Rule. Within the context above, a covered entity is anyone subject to the laws of the USA who wishes to convey health information to anyone else.

Other Data Elements Excluded from PhysioNet Data

In addition to the PHI defined by the HIPAA Safe Harbor Rule, PhysioNet does not distribute data containing any of these elements:

• Identifiers (as defined above by the HIPAA Safe Harbor Rule) of any individual, including those of health professionals and visitors; and
• Names of hospitals, clinics, and other care or research facilities (such as referring hospitals or facilities to which a patient is discharged) with the exception of the hospital or facility at which the data were gathered.

Data Sharing on PhysioNet