2c389a02__Specifications___openEHR_wiki__openEHR_equivalent
[0] 4 [Code mnemonic] NAV [Rubric] temporarily unavailable [Description] Information is not available at this time but it is expected that it will be available later. [openEHR equivalent] 
Q: What information systems can predict te future and reliably set a value like this? What use would it serve? If the data are in fact available later, they will be recorded. Well, the answer is that there is some; like some of the other nullFlavors, the use case is small, but still valid. It's definitely questionnaire related. I don't think it matters to an information system, but a user might make use of this subtlety somehow
Null Flavours and Boolean data in openEHR - Specifications - openEHR wiki
openEHR equivalent