It is critical to understand the 18 PHI identifiers identified by HIPAA (Health Insurance Portability and Accountability Act) Privacy Rules when handling sensitive patient information. These privacy rules establish guidelines for protecting the privacy of individuals' health data, and a comprehensive understanding of these identifiers is necessary for compliance with federal regulations.
De-Identification Standard
De-identification of health information is done by removing all 18 standard PHI identifiers from the data. This process must be done carefully and methodically to ensure complete compliance with HIPAA regulations, and it is based on the expertise of a professional. When de-identifying PHI, it's important to be sure that the data cannot be re-identified in the future. The text of the law describes the standard as this:
"§ 164.514(a) Standard: de-identification of protected health information.
Health information that does not identify an individual and with respect to which there is no reasonable basis to believe that the information can be used to identify an individual is not individually identifiable health information."The law prescribes two ways to go about de-identification: expert determination or the safe harbor method.
Expert Determination
A covered entity may determine that health information is not individually identifiable health information only if:
(1) A person with appropriate knowledge of and experience with generally accepted statistical and scientific principles and methods for rendering information not individually identifiable:
(i) Applying such principles and methods, determines that the risk is very small that the information could be used, alone or in combination with other reasonably available information, by an anticipated recipient to identify an individual who is a subject of the information; and
(ii) Documents the methods and results of the analysis that justify such determination;
The 18 Identifiers for Safe Harbor
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 the 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 that are directly related to an individual, including birth date, admission date, discharge date, death date, 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
(L) Vehicle identifiers and serial numbers, including license plate numbers
(E) Fax numbers
(M) Device identifiers and serial numbers
(F) Email addresses
(N) Web Universal Resource Locators (URLs)
(G) Social security numbers
(O) Internet Protocol (IP) addresses
(H) Medical record numbers
(P) Biometric identifiers, including finger and voice prints
(I) Health plan beneficiary numbers
(Q) Full-face photographs and any comparable images
(J) Account numbers
(R) Any other unique identifying number, characteristic, or code, except as permitted by paragraph (c) of this section [Paragraph (c) is presented below in the section “Re-identification”]; and
(K) Certificate/license numbers
Additional Guidance
You can find additional guidance on the de-identification and re-identification of PHI by referring to this resource (PDF) published by HHS.