The standard tests didn't get it. I actually discovered it when I just totally gave up (at this point I'd been to doctor for numerous blood tests - especially for mono). I cook a lot, and have always eaten fairly well. I just got tired of it... so I ate a lot of terrible food for a month, mostly fried, and I felt awesome. Then i started to get fat. So, i started cooking again. The first meal was beef stew. I ate it, then felt terrible. So I eliminated everything in it, and reintroduced them one-by-one to my diet. The onions were obvious, garlic less so.