I am trying to "peek" at all items dropped (loot messages) and am at the point where I have the item ID from the message, eg " Mïckeyy receives loot: [Thu'rayan Lash]." or "You receive item: [Illidari Shoulders]." and from there I can get item ID: [01:56:02] [Illidari Shoulders]  [Armor] [Leather] [INVTYPE_SHOULDER]
However I have not yet tried it in a party/raid because the documentation of GetItemInfo() says that unless it's in your bags/bank you will not be able to use it.
If this therefore does not work, is there a better way to get information on dropped loot?