1, in vitro allergen detection technology principle When the body is exposed to allergens a series of immune reactions occur. One of the results is the production of an immunoglobulin called IgE. IgE is not a protein, but a class of proteins, and the structure of IgE produced by different types of allergens is slightly different. So scientists indirectly confirm whether a person has been exposed to a certain allergen by testing for the presence of a specific IgE in his or her blood. This method is the in vitro allergen testing technique. For example, if a person is allergic to shrimp, he will have shrimp-specific IgE in his blood after contact with dog hair. if the shrimp column in the allergen test is positive, it means he has been exposed to shrimp and is allergic to this shrimp. 2, false negative Through the previous article you may soon be able to find the shortcomings of the technique. Yes, it is false negative. There are countless allergens in the environment, but there are only 20 or so allergens tested. A negative test does not mean that the person is allergen free. And, even if you are allergic to a certain type of shrimp, the shrimp section of the test report may be negative. This is because the shrimp you are allergic to may not be the same as the shrimp protein antigen used in the test. In addition, when the body IgE decay, the concentration drops to a certain level, the reagent may not be detected and cause false negatives. 3, false positives Any test results may exist false positives. For example, some other proteins in the blood may also be combined with the antigen in the test paper and cause false positives. In addition, an increased IgE titer may not be caused by allergies. For example, parasitic infections, other diseases, etc., may also cause false positives. 4, total IgE The test report usually also reports the total IgE, some in the form of titer, some in absolute value. But no matter which form, usually the higher the value means the higher the concentration of IgE in the body. However, this is not fully correlated with the severity of the disease, so do not deliberately compare the total IgE over different time periods and take this as an indicator of efficacy. 5, to comprehensive interpretation of the report results Understanding the false positives and false negatives of this test, then we should interpret the report according to the patient’s medical history, symptoms, combined diseases other test indicators, etc. to comprehensive interpretation.