Yes absolutely. Susan was very kind hearted and was eager to make a new friend though she didn't give a careful thought to the possibility that her blood type was not going to be a match with Nicole's. Whenever certain types of operations/surgeries are gong to be done then the donor and recipient both must have matching blood types. This is mandatory in the medical world especially whenever blood is being transfused from one patient to another. Though the true culprit was Susan's half brother Aaron who changed the blood type in the lab's database thinking he would cause Susan's death and not realizing that the patient was really Nicole. Susan meant well and didn't know that Aaron was really out to kill her.
