RAST is more accurate, but expensive. No matter what the test shows, you still need to listen to your body more.

If you have been avoiding your food allergens it can throw off the tests as well.

They both really just tell you if you have allergies. They might hint at your worst allergens, but there are a lot of false positives and negatives with both tests.

They are both useful but the determining test is oral. Just because you do or don’t react in the test doesn’t mean you will or won’t react when eating the food.

The skin tests are more susceptible to errors if you've taken any allergy medication, even days before. Whereas the blood test is not affected.