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Today, humanity is increasingly faced with such a phenomenon as allergies. Allergy in most cases is manifested by redness, itching, swelling of the affected area, rhinitis, sneezing, lacrimation. All the symptoms of an allergic patient are caused by our body's immune response to certain substances (allergens). It is the hypersensitivity of immune cells to the allergen that causes an acute inflammatory process - an allergic reaction.
The main principle of allergy treatment is to identify and exclude the substance that caused the allergic reaction. In medical practice, several methods are used to identify provoking substances: skin tests, a blood test for the level of IgE immunoglobulin, a blood test for allergens.
Skin tests
Skin tests are carried out strictly in a medical hospital, as there is a possibility of a severe allergic reaction that requires urgent medical attention. Drops of allergen substances are applied to the inside of the patient's forearm, then the skin under the drop is minimally injured (puncture or scratch). After 10 minutes, an allergic reaction (if any) is manifested by redness, itching, swelling at the site of application of the substance.
Blood test for total immunoglobulin level
The immune response to the ingestion of an allergy-provoking component is always the production of specific antibodies - IgE immunoglobulins (responsible for the occurrence of a lightning-fast reaction) and IgG (which excites an allergic reaction not immediately, but several hours after the allergen enters).
The sampling of venous samples from the patient is carried out in the laboratory in the morning, on an empty stomach. Next, plasma is released, which is divided into several test tubes. In each tube, plasma is mixed with a certain class of substances.
A blood test for total immunoglobulin is not a way to detect specific specific antibodies, but only determines the presence of IgE in plasma. If, according to the results of the analysis, the amount of IgE exceeds the norm (which indicates an allergic reaction), the next type of study is prescribed - a blood test for allergens.
Blood test for specific allergens
This type of analysis is the most informative and safest method for determining a specific substance that provokes an acute immune response.
The sampling of the material is also carried out in a medical laboratory in the morning on an empty stomach. Before taking allergy tests, the patient is recommended:
- do not eat for at least 10 hours;
- do not use tobacco for two hours;
- do not take antihistamines for at least 3-5 days;
- eliminate physical and psychological stress;
- avoid eating potential allergens.
Also, you can not take a blood test for allergens during any inflammatory reactions, infections, SARS, gastrointestinal diseases, exacerbation of any chronic diseases.
Analysis is possible only after 7-10 days after recovery. Failure to follow these rules may lead to incorrect analysis results.
Specificity of a blood test for antibodies
Identification of a specific reaction to a particular substance is possible by two fundamentally different methods:
- MAST CLA . Multiple chemiluminescence method. to special panels with various allergens . When interacting with provoking substances, the blood begins to produce antibodies. At the last stage, special enzymes are applied to the panel, under the influence of which the immunoglobulin begins to glow. Thus, the glow clearly indicates intolerance to specific substances.
- RAST . Radioallergosorbent test. Particles of potential allergens are introduced into blood samples. If the patient has intolerance, the antibody molecules attach to the molecules of the provoking substance. In the process of further processing of the sample with a certain radioactive reagent, the allergen-antibody binding becomes available for detection in a special device.
A blood test for allergens is carried out according to several types of panels that summarize entire classes of substances:
- a panel of food allergens (seafood, citrus fruits, dairy products, canned food, berries, vegetables, fruits, chicken eggs, etc.);
- panel of professional allergens (formaldehyde, ethylene oxide, latex, silk, guar gum, collagen, saccharin, henna, tragacanth, etc.);
- panel of household allergens (house dust, library dust, insect bites, dust mites, pet hair, feathers, etc.);
- a panel of drug allergens (penicillin, analgin, aspirin, iodine, vitamins, bromine, analgesics, etc.);
- a panel of plant allergens (ragweed, cyclahen, nettle, sunflower, wormwood, wheatgrass, rye, plantain, etc.);
- panel of animal allergens (dead particles of animal skin, microparticles of their saliva, urine, excrement);
- panel of allergens of mold fungi (household mold, yeast fungi, saprophytes, smut fungi, etc.).
Each of the allergopanels contains from 2-3 to several dozen components.
Allergen blood test results
Allergen blood testing requires a certain amount of testing time - usually 3-7 days.
According to the amount of IgE immunoglobulin detected, 6 classes of an allergic reaction in a patient are divided:
- Class 0 . IgE level<0.35. Allergic reaction was not detected;
- Class 1 . IgE level 0.35–0.7. Allergies are asymptomatic;
- Class 2 . IgE level 0.7–3.5. Perhaps a slight manifestation of allergy symptoms;
- Class 3 . IgE level 3.5–17.5. Allergy symptoms may be present sporadically;
- Class 4 . IgE level 17.5–50. Allergy symptoms always appear;
- Class 5 . IgE level 50–100. Allergy has pronounced manifestations;
- Class 6 . IgE level >100. An allergic reaction is very acute.
Based on the results of a blood test for specific antibodies, the allergist will write out a treatment regimen that allows the patient to get rid of the manifestations of allergies. And also, if necessary, will draw up a menu that excludes the consumption of not only specific provocative foods, but also foods containing a small amount of intolerable nutrients.
Today, doctors recommend conducting a laboratory blood test for allergens with any suspicion of an allergy, and this is justified - it allows you to identify even hidden forms of allergies (which the patient may not even be aware of) and helps to significantly improve the quality of life of people suffering from manifestations of an allergic reaction.
