Yes, yes, absolutely get bloodwork done! It should be done on a puppy or any pet who has never gone under anesthesia before. My vets require it. It will tell your vet a lot about her organ function and alert him to anything that might anesthesia difficult.
Yorkies especially need pre - op bloodwork done since the breed is prone to liver disease. Anesthesia is processed through the liver.
Please read this:
http://www.yorkietalk.com/forums/yor...-protocol.html
Discuss with your vet beforehand what type of anesthesia he will use. Propofol and isoflurane are the safest for toy breeds.