21833-9

LOINC code 21833-9 identifies "Alternate census tract at cancer diagnosis". This field is provided for coding census tract of patient's residence at time of diagnosis. See Census Tract 1970/80/90 [110]. Codes are those used by the U.S. Census Bureau for the Year 2000 Census. Census tract codes have a 4-digit basic number and also may have a 2-digit suffix. Census tract numbers range from 0001.01 to 9999.98. See the Census Bureau's "Area Classifications" at the following website: http://www.census.gov/prod/cen2000/doc/sf1.pdf for further details. Census tract codes allow central registries to calculate incidence rates for geographical areas having population estimates. This field allows a central registry to add Year 2000 Census tracts to tumors diagnosed in previous years, without losing the codes in data item 110. The Census Bureau provides population data for census tracts. Those rates can be used for general surveillance or special geographical and socioeconomic analysis. Because census tracts for particular cases can change between censuses, the central registry may wish to assign an alternate census tract code to its cases. For example, a registry may code its 1985 cases using both the 1980 and 1990 census tract boundaries. The central registry can use this information for different comparisons... NAACCR Data Standards and Data Dictionary Version 11

This code measures Alternate census tract at cancer XXX Dx in ^Patient. It belongs to the TUMRRGT class in the LOINC classification.

LOINC (Logical Observation Identifiers Names and Codes) is a universal standard for identifying laboratory and clinical observations. It is maintained by the Regenstrief Institute and used worldwide for health data exchange.