An advance directive observation (templateId 2.16.840.1.113883.10.20.1.17) SHALL be represented with Observation. The value for Observation / classCode in an advance directive observation SHALL be 'OBS' 2.16.840.1.113883.5.6 ActClass STATIC. The value for Observation / moodCode in an advance directive observation SHALL be 'EVN' 2.16.840.1.113883.5.1001 ActMood STATIC. An advance directive observation SHALL contain at least one Observation / id. An advance directive observation SHALL contain exactly one Observation / statusCode. The value for Observation / statusCode in an advance directive observation SHALL be 'completed' 2.16.840.1.113883.5.14 ActStatus STATIC. An advance directive observation SHALL contain exactly one advance directive status observation. An advance directive observation MAY contain exactly one advance directive reference.