Not, all test are 100%. The two main ones are the skin and RAST (blood test). If it's been a while since your last allergy appointment, set up another one. Redue the skin test. Just like Red_34, I also had the RAST tests done and they have basically came back negative, however I have anaphylactic reaction just to inhalation of some of my food allergies. Also some skin tests can give a false reading. That is why a good history should be taken, and not just relied on tests.
As for the peanuts, if it's just nuts you react to, peanuts should be fine (because they are not a nut, they're legumes), however, crosscontamination is high. Best to avoid all nuts and peanuts. Also, it's probably best and not to mention the safest (especially if it scares you, which it would anyone) to just stop eating at chiness restraunts and buffets etc..
If this is an allergy, your immune system is not bad, it's not rundown.... it's the opposite, it's a hypersensitivity. Ex. this is just me, but before I had all these anaphylactic reactions I use to get colds and flu, just like everyone else. When my family had a cold, i'd catch it. But the last 4 years, I have not had a single cold, flu, or anything like that. But again,this is me. I know others who have allergies and still get colds etc.
The only thing you can do for a food allergy is strict avoidence, and be prepared for a reaction.