This code system http://terminology.hl7.org/CodeSystem/data-absent-reason defines the following codes:
Lvl | Code | Display | Definition | Comments |
1 | unknown | Unknown | The value is expected to exist but is not known. | |
2 | asked-unknown | Asked But Unknown | The source was asked but does not know the value. | |
2 | temp-unknown | Temporarily Unknown | There is reason to expect (from the workflow) that the value may become known. | |
2 | not-asked | Not Asked | The workflow didn't lead to this value being known. | |
2 | asked-declined | Asked But Declined | The source was asked but declined to answer. | |
1 | masked | Masked | The information is not available due to security, privacy or related reasons. | Using "masked" may be breach of security or confidentiality, but there are times when its use is required to support alternate workflows for gaining access to denied information. |
1 | not-applicable | Not Applicable | There is no proper value for this element (e.g. last menstrual period for a male). | |
1 | unsupported | Unsupported | The source system wasn't capable of supporting this element. | |
1 | as-text | As Text | The content of the data is represented in the resource narrative. | It may be linked by internal references (e.g. xml:id). This usually implies that the value could not be represented in the correct format - this may be due to system limitations, or this particular data value. |
1 | error | Error | Some system or workflow process error means that the information is not available. | |
2 | not-a-number | Not a Number (NaN) | The numeric value is undefined or unrepresentable due to a floating point processing error. | This is sometimes an output value from measuring devices. |
2 | negative-infinity | Negative Infinity (NINF) | The numeric value is excessively low and unrepresentable due to a floating point processing error. | This is sometimes an output value from measuring devices. |
2 | positive-infinity | Positive Infinity (PINF) | The numeric value is excessively high and unrepresentable due to a floating point processing error. | This is sometimes an output value from measuring devices. |
1 | not-performed | Not Performed | The value is not available because the observation procedure (test, etc.) was not performed. | |
1 | not-permitted | Not Permitted | The value is not permitted in this context (e.g. due to profiles, or the base data types). | This is most often associated with required bindings that do not include the actual code used, but may be used with other data types. |