Removal of medical record number and of patient identifiers will be conducted by following the HIPAA “safe harbor” method as defined by the HIPAA Privacy Rule, (CFR 164.415 (b) (2). This method results in removing the following data elements:

  • Names.
  • All geographic subdivisions smaller than a state, including street address, city, county, precinct, ZIP Code, and their equivalent geographical codes, except for the initial three digits of a ZIP Code if, according to the current publicly available data from the Bureau of the Census: 
    • The geographic unit formed by combining all ZIP Codes with the same three initial digits contains more than 20,000 people.
    • The initial three digits of a ZIP Code for all such geographic units containing 20,000 or fewer people are changed to 000.
  • All elements of dates (except year) for dates directly related to an individual, including birth date, admission date, discharge date and date of death. In addition, 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. 
  • Telephone numbers.
  • Facsimile numbers. 
  • Electronic mail addresses.
  • Social security numbers.
  • Medical record numbers.
  • Health plan beneficiary numbers.
  • Account numbers.
  • Certificate/license numbers.
  • Vehicle identifiers and serial numbers, including license plate numbers.
  • Device identifiers and serial numbers.
  • Web universal resource locators (URLs).
  • Internet protocol (IP) address numbers.
  • Biometric identifiers, including fingerprints and voiceprints.
  • Full-face photographic images and any comparable images.
  • Any other unique identifying number, characteristic, or code, unless otherwise permitted by the Privacy Rule for re-identification.

In order to de-identify dates, the CRDW staff will shift all dates from the EMR 1–365 days into the past. The shift will be different across records, but constant within the records of each patient. This will allow temporal analyses such as the development of adverse effects after a drug.


The HIPAA Privacy Rule (CFR 164.514 (c) allows for the assignment of a code — referenced as anonymous ID — or other means of record identification to allow information de-identified under this section to be re-identified by the covered entity, provided that:

  • 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.
  • 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.