I rarely pre-wash--but I always pre-test! I take a slip of white paper and rub REALLY hard on the fabric, especially if the color is dark or looks heavily dyed. If ANY color shows on the paper, then I will just wash, cold water/short cycle/regular detergent. Otherwise I like the fabric to retain it's sizing which makes it easier to cut and handle without fraying (and I don't have allergies to the sizing, etc).
Then, the first time I wash the completed quilted I will use cold water, Woolite or Orvus or quilt soap, and always throw in 2-4 Color Catchers (depending on quilt size).
As far as shrinkage is concerned, I put any washed fabric into the dryer for a short, mostly dry, cycle and pull out and use my steam iron to dry it completely--gets the wrinkles out and will shrink it at same time.