2c389a02__Specifications___openEHR_wiki__openEHR_equivalent
[0] 1 [Code mnemonic] NI [Rubric] no information [Description] The value is exceptional (missing, incomplete, improper). No information as to the reason for being an exceptional value is provided. This is the most general exceptional value. It is also the default exceptional value. [openEHR equivalent] 
(same in openEHR)
Null Flavours and Boolean data in openEHR - Specifications - openEHR wiki
openEHR equivalent