It is possible to eat oranges before having an antigen test, but only if you are not allergic to oranges. Eating oranges before an antigen test will not usually affect the results of the antigen test. Before the antigen test, it is best not to eat foods that can cause allergies, such as seafood, mango, and high-protein foods. These may cause an allergic reaction, and an allergic reaction may lead to abnormal antigen test results, so if you are allergic to oranges yourself, you should not eat them. Antigen testing can be used to detect viral infections. For example, Hepatitis B surface antigen, AIDS antigen and so on. Generally, the components of oranges will not affect the antigen test. Usually on many laboratory indicators before the test are required to fasting, it is recommended that before the test to consult with the test doctor, to avoid affecting the results of the test.