WoW API: Active Runecarving Power passive effect(s)

Is there a better a better API method for determining whether or not a player has a specific Runecarving Power passive effect than checking IsEquippedItem(key) for every possible legendary item that can have that Runecarving Power? Thanks!

Edit: The issue is that the name of some legendary items is not the same as the Runecarving Power that is associated with that legendary. For example, the legendary that is crafted from the Crimson Rune Weapon Runecarving Power and goes in the shoulder slot is called “Shoulderguards of the Crimson Rune”. So, you can’t just use IsEquippedItem(“Crimson Rune Weapon”) to determine whether the player has the Crimson Rune Weapon passive effect.