What are CBC and electrolyte tests

My Dr. wants me to be tested for CBC and electrolytes a week before the surgery on 6/26/01. 1. What are these tests? 2. Why couldn't they get that info from the blood I gave to the endocrinologist 3 weeks ago? Just curious, and I asked him so many other questions, I forgot to ask this.

We greatly appreciate your interest in helping us build our Q&A database. To discourage vandals from posting garbage, however, we require people to register before posting.