Preventative health screenings: Where do you start?

www.amsat.com

Does anyone have any advice on this?
I've seen advertisements for AMSAT everywhere. There’s a similar clinic in Seattle—I think it was run by a Dr. Sanja Zutic or someone like that...
Anyway, I want to know if anyone has actually been there. What are your impressions? Is it worth the money?

I suffer from frequent illness and exhaustion due to a weak immune system. I'm considering pairing this with a standard blood panel.

We touched on this earlier, so take a look here
CNN 1
CNN 2