They do use blood. Hence the bloodstones.
From the OP:
Do people read before they respond?Transfusion (channeled)= Drain blood from a target, healing the Blood Mage in the process. Blood Mages harden thisr life force into a Bloodstone for later use. Can carry up to 10 Bloodstones at a given time.
Bloodstone= A magical stone created from blood. Used to power arcane magic.