How should I complete a data field (a field where a user can type information) if I do not have information for the field?

For Health Level Seven (HL7) Individual Case Safety Reporting users, the HL7 ICSR schema provides for several values that may be used when there is no information to enter in an optional field:

1. ASKU – asked but unavailable
2. NI – no information
3. NA – not applicable