Accepted values can be added, removed or edited in the screen above.
If we wanted to validate zip codes, states, countries, CPT codes, or ICD codes, for example, we could also add them using the same method. The issue, however, is that these lists are much larger. This is where code lists enter the picture. They allow an element’s accepted values to be located in an external file. They are now called External Code Lists.
The first step is to create an external code list. Let’s create a file called States.txt and add a few accepted values to it. Only the code is required, the description is optional