Item Uniqueness and Unique-Equipped Key

How can I detect item uniqueness and the key for a unique-equipped count (1) from the item web api?

Example:

http://www.wowhead.com/item=79328
Unique-Equipped: Darkmoon Card of the Mists (1)

http://us.battle.net/api/wow/item/79328
Nothing mentions "Darkmoon Card of the Mists" or Unique

Thanks!