Thanks for your comments. I found on the American Academy of Allergy Asthma & Immunology that anaphylaxis, while rare, can happen with OAS, so trial and error seems frightening. If blood and skin tests come back negative, it seems like every food you try to eat may cause a life-threatening problem. My allergist mentioned the possibility of oral challenges, in which I'd eat a food in his office and they would observe me to see what happens. I think that's going to be the way to go. Thanks!