User blog comment:Xilinoc/Ch. 542 - THE BLADE IS ME/@comment-10699642-20130619212112/@comment-4207271-20130620110706

Uryu isn't full blood, he is just descended from a very powerful line of Quincies, Katagiri (Uryu's mother) was a half-blood, so Uryu is at best 3/4 pure blood