I hadn't heard of ALCAT but looked it up, and my doctor did similar tests for me using York Test. It's quite expensive as it has to go to the US for analysis - think it was around S$400 - but IME well worth it.
I found out a whole host of intolerances. Avoiding the major foodstuffs and retesting after a year, a few of my intolerences have gone from high to low and I'm managing the others - I have chronic autoimmune disorder so this is important to me.
My doctor is Ian Lee at the Integrated Medicine Clinic at Biopolis. He's very knowledgeable in this area.
http://www.integratedmedclinic.com/index.html