Beginning in 2008, Arizona no longer captures foreign resident status in ZIP Code. This information is retained in the data element Patient Country. During processing, we use Patient Country to recode the ZIP Code field. Canadian residents are coded to "Canada" (ZIP="C"), Mexican residents are coded to "Mexico" (ZIP="M"), and all other valid Patient Country codes are mapped to "Foreign" (ZIP="F").

Through 2007, Arizona codes a five-digit abbreviation for the country of foreign residents. Canadian residents are coded to "Canada" (ZIP="C"), Mexican residents are coded to "Mexico" (ZIP="M"), and all others are coded to "Foreign" (ZIP="F").

Arizona provides a source category for transients and homeless ("TRANS"). From 2000-2007, this code was assigned to the HCUP category for Homeless (ZIP = "H"). Prior to 2000, this code was recoded to blank (ZIP = " "). Beginning in 2008, this category is no longer provided.

California reports a single "Area Outside the U.S." category which includes Canada and Mexico. During HCUP processing, "Area Outside the U.S." was assigned to the uniform category "Other/Unspecified Foreign" (ZIP_F="F").

Beginning in 1992, California reports a separate zip code category for homeless patients. Beginning in 2000, this zip code was assigned to the HCUP category for Homeless (ZIP="H"). Prior to 2000, this zip code was recoded to blank (ZIP=" ").

In 1993, Colorado redefined zip code categories and included a separate category for foreign and homeless patients. Colorado used only one category for all foreign zip codes, including Canada and Mexico. These are assigned to the HCUP category for Other/Unspecified Foreign (ZIP = "F"). Colorado used the zip code "00003" for homeless patients. Beginning in 2000, this zip code was assigned to the HCUP category for Homeless (ZIP = "H"). Prior to 2000, this zip code was recoded to blank (ZIP = " ").

District of Columbia uses only one category for all foreign zip codes, including Canada and Mexico. These are assigned to the HCUP category for Other/Unspecified Foreign (ZIP = "F").

Beginning in 2010, the data element "Patient Country" is used to determine Canadian, Mexican, and other or unspecified foreign zip codes. A single "Foreign Country" category which includes Canada and Mexico is used when "Patient Country" is missing.

Prior to 2004, Florida masked zip codes of areas in Florida where the population is less than 500 people and also for patients who reside out of state. These masked codes were set to missing (ZIP = " ") during HCUP processing. Beginning in 2004, Florida provides HCUP with unmasked zip codes for all records.

Florida reports a single "Foreign Country" category which includes Canada and Mexico. During HCUP processing, "Foreign Country" was assigned to the uniform category for "Other/Unspecified Foreign" (ZIP = "F").

Beginning in 1997, Florida reports a separate zip code category for homeless patients. Beginning in 2000, this zip code was assigned to the HCUP category for Homeless (ZIP = "H"). Prior to 2000, this zip code was recoded to blank (ZIP=" ").

Due to an error in HCUP data processing, the Florida 1990 supplemental file is missing ZIP_S.

Georgia does not separately classify Canadian, Mexican, or other foreign zip codes.

Indiana classifies foreign ZIP Codes as a group and does not separately distinguish Canadian or Mexican ZIP Codes.

Iowa does not code foreign zip codes. Any non-U.S. zip codes would appear as missing (' ') or invalid ('A').

Kentucky uses only one category for all foreign zip codes, including Canada and Mexico. These are assigned to the HCUP category for Other/Unspecified Foreign (ZIP = "F").

As of July 17, 2019, skinny files containing the patient's ZIP Code (HCUP data element ZIP) are available for data years 2008 through 2017. Users can link the year-specific skinny ZIP Code files to the same year Core file by using data elements YEAR and KEY. Starting in data year 2018, the data element ZIP is stored on the Core file.

Beginning in 2013, Maryland reports a separate zip code category for homeless patients which was assigned to the HCUP category for Homeless (ZIP="H").

Beginning in 1993, Maryland reported a separate category for "foreign" zip codes which includes Canadian and Mexican zip codes. During HCUP processing, foreign zip codes were assigned to the category "Other/Unspecified Foreign" (ZIP = F).

Prior to 1993, Maryland did not separately classify "foreign," Canadian, or Mexican zip codes. During HCUP processing, all foreign, Canadian, and Mexican zip codes were assigned as missing (ZIP = blank).

Michigan reports four separate ZIP Code categories for Sault Ste. Marie, Sarnia, Windsor, and "All other Canada." For 2001-2002, the ZIP Code category for "All other Canada" was recoded to blank (ZIP=" "). Beginning in 2003, this ZIP Code was also assigned to the HCUP category for Canada (ZIP="C").

Beginning in 2001, Michigan supplies a five digit patient ZIP Code and identifies foreign residents. Canadian residents are coded to "Canada" (ZIP="C") and all others are coded to "Foreign" (ZIP="F").

Prior to 2001, Michigan only supplied the first three digits of the patient's ZIP Code, ZIP is blank ("").

Beginning in 2016, Minnesota separately classifies Canada zip codes from other foreign zip codes. Prior to 2016, Minnesota used only one category for all foreign zip codes, including Canada and Mexico. These are assigned to the HCUP category for Other/Unspecified Foreign (ZIP = "F").

Mississippi does not separately classify Canadian, Mexican, or other foreign zip codes.

Missouri reports all Canadian, Mexican, and other foreign zip codes as a single category. These codes were assigned to the uniform category "Other/Unspecified Foreign" (ZIP = F).

Missouri reports a separate zip code category for homeless patients. Prior to 2002, processing, this zip code is recoded as missing (ZIP = blank). Beginning in 2002, this zip code is recoded to Homeless (ZIP = H).

Nebraska does not separately classify Canadian, Mexican, or other foreign zip codes.

Beginning in 2008, C(Canada), M(Mexico), F(Other or unspecified foreign) were assigned from patient country codes during the HCUP processing.

New Jersey does not report foreign, homeless, Canadian or Mexican zip postal codes. In the source data, these ZIP codes are blank. During HCUP processing, blank values were assigned to missing (" ").

Beginning in 2016, HCUP stopped assigning F (Foreign) and H (Homeless) using the Flag_Res variable. H (Homeless) will no longer be a value assigned under zip.

Beginning in 2008, for HIV/AIDS records in New York, the last two digits of the zip code is blank if the population is greater than 20,000. If the population is 20,000 or less, the entire zip code is blank.

Beginning in 1993, New York separately classifies Canadian, but not Mexican zip codes. Mexican zip codes are included in the HCUP category for Other/Unspecified Foreign (ZIP = "F").

For 1988-1992, New York uses only one category for all foreign zip codes, including Canada and Mexico. These are assigned to the HCUP category for Other/Unspecified Foreign (ZIP = "F").

North Carolina does not separately classify Canadian, Mexican, or other foreign zip codes.

Prior to 2017, Oregon reports foreign, Canadian, or Mexican zip codes as "missing" or "invalid" ZIP code values. These are assigned to the HCUP category for missing (ZIP = blank) or invalid (ZIP = .A).

Starting in 2017, Oregon reports foreign zip codes. However, Oregon does not separately classify Canadian or Mexican zip codes. Foreign zip codes are assigned to the HCUP category for Foreign (ZIP = "F").

Rhode Island does not separately classify Canadian, Mexican, or other foreign zip codes.

South Dakota does not separately classify Canadian, Mexican, or other foreign zip codes.

Utah uses only one category for all foreign zip codes, including Canada and Mexico. These are assigned to the HCUP category for Other/Unspecified Foreign (ZIP = "F"). Beginning 2015, Utah no longer reports homeless patients in a zip code category. Homeless patients are identified by condition code value 17.

Through the 2002 data year, Utah masks zip codes under the following conditions:

• Patients in Utah or non-Utah zip codes with less than 30 discharges in a calendar year,
• Patients with the Major Diagnosis Code of "Human Immunodeficiency Virus Infection" (value 25), and
• Diagnosis Related Groups "Alcohol/Drug Abuse or Dependence" (values 433-437).

During HCUP processing, the masked zip code is recoded as missing (ZIP = blank).

Utah reports a zip code category for homeless patients. Beginning in 2000, this zip code was assigned to the HCUP category for Homeless (ZIP = "H"). Prior to 2000, this zip code was recoded to blank (ZIP = " ").

Beginning with the 2015 data, the HCUP data element ZIP is set to missing (.) in the Central Distributor SID for records involving substance abuse or HIV infection. This was done at the request of the Utah Partner organization.

Canadian residents are coded to "Canada" (ZIP="C") and all other foreign discharges are coded to "Foreign" (ZIP="F"). Homeless patients are not identified.

Due to an error in 2004 HCUP processing of the Washington SID, the ZIP Code for less than 100 foreign discharges was set to invalid ("A") instead of set to unspecified foreign ("F").

Wisconsin uses only one category for all foreign zip codes, including Canada and Mexico. These are assigned to the HCUP category for Other/Unspecified Foreign (ZIP = "F").

Prior to 2006, Wisconsin suppressed zip codes with low frequency (less than 30 discharges per quarter) or low population (less than 1000 people). These zip codes will appear as missing (" ") in the HCUP Wisconsin data.