GED question..Please help.

I am living in California right now and have a California high school proficiency. I was looking at what I have to do to get a GED and am unsure of the difference from state to state. I did read that every state has its own requirements. My husband and I are planning to move to Washington State next year. I would like to go to college there. So my question is can I take the GED test here in CA and have it be valid in WA or do I need to take the GED test in WA? Any input is greatly appreciated. Thank You.