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Health

How to pass allergy tests?

, medical expert
Last reviewed: 23.04.2024
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Treatment of allergies can only be effective if the allergen provoking the immune response is detected in a timely manner. To pass analyzes on an allergy means to reveal causative agents of an aggressive response of an organism which can react to following groups of allergens: 

  • Household - wool, dandruff and animal products (saliva, urine), household dust.
  • Nutritional - protein cow milk, citrus fruits, nuts, seafood, eggs, chocolate, berries, vegetables and fruits of red color and so on.
  • Vegetable - pollen of plants and trees.
  • Medication - medicines (most often antibiotics).
  • Industrial - glue, household chemicals, paints, perfumes.
  • Insect - bites of wasps, bees, mosquitoes.
  • Viral - pathogens of various diseases, bacteria, viruses, fungi.

It should be noted that, in determining the main antigen or hapten, there are objective difficulties associated with the fact that in the last ten years a single-component allergy is practically not found, a cross-sectional disease is much more often diagnosed. Therefore, to pass tests for allergies means to undergo a whole complex of examinations, helping to identify the most dangerous allergy substances.

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How it is possible to hand over analyzes on an allergy?

Any medical examination begins with the collection of anamnesis, that is, complaints, signs and symptoms of the disease, specificity of its development, heredity and conditions under which the allergy is manifested particularly intensively. Methods for testing an allergic patient can be divided into two categories: 

  • In vivo - with direct participation in the process of the patient himself (skin tests, provocations).
  • In vitro - only blood serum is needed.

Then, analyzes are given, which can be performed by the following methods: 

  1. Scarification skin tests.
  2. Identification of specific immunoglobulins, Ig Ig antibodies. 
  3. Provocations, provocative tests.
  4. Elimination test.

Skin scarification tests.

The study is carried out with the help of scarification (scratches) or with the help of peak testing (prick) and is aimed at identifying a group of allergens that cause typical allergic symptoms. These methods are considered painless and are performed on the skin in the forearm area. The skin area is treated with an antiseptic, the allergen is drip onto it. If it is recommended to pass allergy tests with the scarification method, then the skin is scratched by the scarifier directly through the drop with allergens. If a peak test is prescribed, small injections are applied through the drop using a sterile disposable needle. Both methods are absolutely bloodless, as they assume only superficial damage to the skin. Usually, no more than 15 samples are taken once. The reaction of the body manifests itself after 15 or 20 minutes as a small localized edema and redness. There is also a completely non-aggressive method - an application (patch test), when a special patch is applied to drops with an allergen, the patch is attached to the skin. Reaction of skin in the form of itching, congestion, swelling indicates a positive response to the presented allergen. All these methods have contraindications: •

  • Children under 5 years.
  • If a history of anaphylactic shock is indicated.
  • Pregnant women and women breastfeeding.
  • Age after 60 years.
  • Hormonal therapy.
  • Exacerbation of diseases - allergic, gastrointestinal, cardiological, nervous and others.

Determination of antibodies IgE and IgG4 or quantitative determination of specific immunoglobulins

This method (in vitro) is considered highly sensitive and determines the entire group of true provoking allergens. The fact is that initially in the blood contains a small amount of Ig E, with allergies with an immediate reaction, this amount significantly exceeds the limits of the norm. The way to identify specific antibodies most often helps to identify food allergens, which complements the diagnostic information obtained by provocative or dermal methods. The method is very convenient because it is possible to take tests for allergies during an exacerbation of both an allergic reaction and an exacerbation of another disease. In addition, the definition of immunoglobulins is not contraindicated in pregnant women, elderly patients and children. The analysis requires blood from the vein 3 hours after eating.

Also, the RAST method, a radioallergosorbent test, is effective, which detects the level of IgE when specific triggers are introduced - allergens. The RAST method is good because its results are not affected by drug therapy, including antihistamines, and is suitable even for examination of young children.

Method RIST (radioimmunosorbent paper indicator). The method is effective for allergic rhinitis, bronchial asthma, sinusitis and bronchitis. RIST provides a fairly informative and accurate picture of the level of antibodies IgE and IgG.

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Provocative methods

Provocative tests are necessary in cases where skin tests and IgE levels do not provide an accurate diagnostic picture and the doctor has doubts about the true causative agent of the disease. Provocations are conducted only in hospitals under strict medical supervision. The method involves the introduction of a small amount of the allergen sublingually (under the tongue), nasally (in the nose), less often directly into the bronchi. The interaction of the allergen with the body takes a certain amount of time, then assesses the symptomatology, that is, the reaction. Of course, allergic symptoms can manifest themselves quite intensively, which is why provocations are prescribed quite rarely and under strict medical indications.

Elimination tests.

It happens that the allergic reaction occurs periodically, but more often the organism has the property of constantly reacting to a certain stimulus. The method of elimination (elimination) determines the provocative substance. A good example is the elimination diet, when "suspicious" products are gradually withdrawn from the ration of the allergy sufferer, the patient's condition is monitored, symptomatology is assessed. As a rule, with the correct "guess" and exclusion of the allergen after a couple of weeks, there is a noticeable relief and a decrease in the allergic reaction.

Also, in addition to the fact that an allergy sufferer will need to pass allergy tests, a good guide in monitoring the condition is keeping a "diary of an allergy", which describes all cases of reaction to various stimuli, time and intensity of symptoms.

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