Can there be a test you can get which can tell you if you are allergic to anything?

No: The history of any illness drives the diagnosis . The testing is an objective means to provide support for the diagnosis. However those with higher blood ige levels are more likely to have or develop allergic diseases. However it is not a certainty. In allergy, the presence of an allergic disease in one or more parents of your family is one of the best predictors.