The only true diagnosis of a food allergy is whether an individual has had an allergic reaction to a food. Sometimes this can be difficult as not all foods are eaten in isolation of one another. The next best step is to discuss allergy testing with a medical professional. Following are some things you should know about allergy testing.
There are two types of tests A skin prick test and a blood test. Some doctors will choose to do one or the other and some will do both. Both tests can give false positive or negative results, so it is important to weigh the results with your reaction history.
An allergic reaction prior to testing can cause mixed, poor or false results If an individual has experienced a reaction, the body is in a heightened sense or state and can cause the testing results to appear higher than they might normally be. Most allergists recommend waiting several days to a week after a reaction before testing is done.
Be careful with your medications Antihistamines should not be taken for up to a week before testing as they too can interfere with testing results. Discuss with your allergist any other medications that might be problematic.
Consider a food challenge If there is no definite history of reaction to a food, yet testing results come back positive--you may want to discuss scheduling a food challenge with your allergist.
Food allergies and testing are a tricky thing. One must balance the pros and cons of allergy testing, results and potential food avoidance (depending on those results) in combination with a history of reaction—so that a food in not avoided unnecessarily.