It varies from vet to vet really - for example, my vets charge £37 for the pre-op bloods DAwn mentioned. My vet always gives a scale of between x and x, but prob in the middle, or nearer the top end, it all depends on what they have to do, and the anaesthetic normally goes off their weight, so Gingers were always more than Pebbles, as he was nearly 2kg heavier.