There is an ever rising number of people with allergies across the world. The main indicators of allergies include sneezing as a result of weather change, teary and itchy eyes in dusty home or homes with pests and other animals.
Blood tests are normally run where the exact cause of an allergy is unknown making it very difficult to determine the best course of treatment for your allergy.
Who needs blood allergy tests?
Not every person thought to be allergic goes for blood allergy tests. Persons who are recommended to take the blood allergy tests include:
- People using medicine that is known to interfere with normal results yet they cannot stop taking the medication. Such medications include antidepressants, steroids, and antihistamines.
- Persons unable to tolerate the needle scratches necessary for skin testing of allergies.
- Persons with unstable heart conditions
- Individuals prone to extreme reactions or anaphylaxis
- Individuals with poorly managed asthma
Types of blood tests for allergies
There are two main procedural tests run when ascertaining the cause of an allergic reaction. They include:
- Enzyme-linked Immunosorbent assays (ELISA)
- Radioallergosorbent test (RAST)
Both tests detect the presence and the levelof allergen-specific antigens in your blood. An allergen is any trigger that causes a reaction when you come in contact with it.
Once an allergen is in the body, antibodies are formed against the allergens. At the same time, the antibody cells activate the release of bio-molecules and biochemicalsthat cause the allergy symptoms.
The antibody strongly associated with allergies is IgE or Immunoglobulin E. The above-mentioned allergy blood tests are used to screen allergies for dust, trees, pet dander, weeds, or mold. They are also important for diagnosing food allergies.
IgE and other antibodies have been shown to cause de-granulation of basophills and mast cells in vitro. The de-granulation causes activation of complement cascades that will be found to be in high levels circulating in blood.
There are various ELISA testing kits in the market for research and clinical use. The testing kits for allergies are normally predesigned with the antigen-specific antibodies attached to the testing kit’s solid matrix.
There are four main types of ELISA tests: direct, indirect, sandwich, and the competitive ELISA. The indirect ELISA test is often used for allergies though the competitive and the sandwich assay can also be used.
ELISA tests are high on the list of recommended allergy blood tests because they are highly sensitive, safe, and economical. Besides measuring the presence and the levels of IgE in blood, these tests also determine the presence of IgG, another antibody whose levels are high in allergic reactions.
The radio allergosorbent test is used to detect the presence of IgE antibodies when determining what a person could be allergic to. It is mainly employed in treatment of Type I allergic reactions.
In conclusion, allergies whose causes cannot be determined normally are determined or tested by running blood tests. There are blood-testing kits for ELISA and RAST tests and the results have always been conclusive whenever they are run.
Isabella Rossellinee is a renowned biochemist working with a leading biochemical firm to design testing kits for various diseases.