Among allergy test methods, the one with the lowest analytical sensitivity is the measurement of specific IgE. Because there are five types of immunoglobulins (Ig) produced in the human body (IgG, IgM, IgA, IgD, IgE). Of these, the one with the lowest percentage in serum is IgE (0.002%). In mild allergic reactions caused by mild allergens, there will be a slight increase in serum levels. Since the percentage of IgE is already very low, the response of IgE at low concentrations cannot be detected; thus, although there is an in-vivo allergic response in the body, false negative results can be reported with in-vitro IgE-based laboratory tests outside the body, as the low concentration cannot be detected. In this context, we can consider IgE-based allergy tests (especially in cases of mild and moderate allergic reactions) as a group of useless tests.

The analytical sensitivity of IgG-based tests is higher. Food intolerance tests (IgG) may be recommended. With a single test, the presence of intolerance to dozens of different foods can be detected. IgG is the immunoglobulin type with the highest percentage in serum (80%).

Among all allergic laboratory measurement tests, the ones with the highest analytical sensitivity are the Lymphocyte and Leukocyte-based Cell Culture Tests, which have been developed and introduced in recent years. Lymphocyte Transformation Test (LTT) and Leukocyte Activation Test (LAT). Both tests are also known as food sensitivity tests. The presence of sensitivity to dozens of foods and various non-food allergens can be determined by a test.

In addition, Histamine Intolerance Tests can also be applied in the determination and monitoring of allergic reactions.

1. Determination of histamine levels (serum and/or fecal histamine levels)
2. Genetic test for histamine intolerance
3. Determination of diamine oxidase (DAO) enzyme levels (DAO; the main enzyme responsible for histamine breakdown).