Can you give me the low-down on blood tests? Accuracy, etc?

[Ophelia]

I asked about this a little bit before, but would like more specifics. Basically I would like to know:

-What different kinds of tests are there (ELISA, RAST, etc)?
-What is the difference and what is more reliable?
-Do you just ask for everything to be tested (all food, environmental allergies)?
-What labs are the best?
-Does it seem to vary a lot on how accurate they are?

Is there another thread or reliable website that already has this info? thanks!

[changingseasons]

Check my blog (link in sig.)