What tests are handed over for an allergy. Allergen testing: how it's done. Methods of laboratory diagnostics

The term "allergy tests" or "allergy tests" refers to 4 types of tests:

  • skin test,
  • blood test to determine the total level of immunoglobulin E,
  • blood test for the determination of specific antibodies,
  • provocative tests.

For staging accurate diagnosis the results of one or two of the listed tests are required. The examination begins with skin tests. If there are contraindications, resort to more safe method diagnostics - a blood test for antibodies. A provocative allergen test is used only in extreme cases: if there are discrepancies between the results of studies already conducted and the patient's medical history (for example, a survey shows that the patient is allergic to birch pollen, but skin tests do not confirm this).

Allergies to various substances most often manifest the same symptoms. It is difficult to determine the cause of an allergy without resorting to special skin tests, more commonly called allergy skin tests. This method is the most common in allergology, and is used to establish an accurate diagnosis.

Allergy tests are carried out for diseases such as:

  • bronchial asthma, manifested by recurring signs of suffocation as a result of bronchial spasm when exposed to allergens;
  • allergic dermatitis characterized by rashes, redness and itching;
  • pollinosis or allergy to flower pollen, which is manifested by rhinitis, conjunctivitis, sneezing and runny nose;
  • food allergy characterized by skin rashes, redness and itching.

How are skin tests done?

Skin tests for allergens are scarification, with skin piercing (prick tests) and intradermal. In the first two cases, the procedure is quite simple. On the skin of the patient's back or forearm, the doctor applies solutions of "interested" allergens - no more than 15-20 per procedure. Under the drops, using a special plate, scratches are made (scarification method) or shallow injections with a thin needle (prik method). It doesn’t take long to languish in ignorance - the doctor evaluates the results of the samples in 20 minutes.

Dermal allergic tests do not carry out:

  • during an exacerbation of any chronic disease (allergies in including),
  • during acute infectious diseases,
  • children under 3 years old,
  • pregnant and lactating women.

In addition, it is not recommended to resort to this research method for women in the early days. menstrual cycle. Due to what happens in the body hormonal changes test results may be inaccurate. In order to take an allergy test, the patient is asked to prepare in advance:

2 weeks before the procedure, stop taking internal antihistamines,

stop using anti-allergic ointments for a week.

Animal allergens: animal dander, mixture ( overall result): cats, horses, golden hamster, dogs

Individual allergens (1 allergen)

Animal food panel (individual result): lamb, beef, turkey, shrimp, chicken, salmon, cow's milk, goat's milk, egg white, egg yolk, pork, cheddar cheese, cod, tuna, hake

The term "skin tests for allergies" refers to a method for determining the allergen, characterized by the highest information content. Relatively simple technique is effective and practically does not bring any discomfort to the patient. Before starting the test, it is important to find out all the indications for the appointment, as well as contraindications. In addition, it is necessary to properly prepare for prick tests, scarification tests, as well as special applications.

An allergic reaction may be caused by great amount factors and substances, including:

  • alcohol;
  • mold and all types of fungus;
  • pollen;
  • most foodstuffs;
  • cosmetics and household chemicals;
  • wool;
  • ultraviolet;
  • medicines and so on.

The symptomatology of an allergic reaction does not depend on the irritant, therefore, it is often quite difficult to identify the allergen through a survey and examination.

In some more complex cases, a person's immunity is sensitive to several allergens at the same time, which further complicates the final diagnosis.

The following symptoms are considered indications for skin tests:

  • allergic cough and asthma;
  • skin irritations, including eczema, urticaria, rashes;
  • itching of mucous membranes and skin;
  • nasal congestion, runny nose,;
  • migraines, headaches, dizziness;
  • conjunctivitis;
  • disorders nervous system, dizziness;
  • malfunctions of the gastrointestinal tract, constipation and diarrhea;
  • Quincke's edema and so on.

Before you learn how allergy skin tests are done, you need to understand in which cases the test is performed. The technique helps to identify the irritant:

  1. If the irritant had contact with the skin of an allergic person, accompanied by interaction with mast cells;
  2. If allergic symptoms manifests itself when the irritant penetrates the wound;
  3. If the area of ​​​​the skin of the water is itchy, swollen and reddens due to the effect of the applied allergen.

As a result of the test, the doctor determines an irritant or a group of irritants that it is important for an allergic person to exclude from everyday life.

The essential elements of this diagnostic method include extracts and solutions of various allergens. In order for the result of the study to be extremely clean, doctors use histamine and glycerin. More samples show a response to histamine, since the absence of any response on the skin most often indicates a test error. The test is carried out using a tampon applicator, lancet or a special needle.

Allergy skin tests: contraindications

It is forbidden to hold this study v the following cases:

  • when an allergic person suffers from infectious diseases, including tonsillitis, bronchitis, pneumonia, and so on;
  • when a patient has AIDS or any other autoimmune pathology;
  • when the risk of occurrence is high;
  • during pregnancy or lactation;
  • if the allergic person suffers from mental disorders;
  • when a malignant neoplasm is diagnosed.

Experts categorize everything possible contraindications into two groups: absolute and relative. Some diseases are considered a relative contraindication, in which it is strictly forbidden to administer an irritant even in minimal doses. However, the study can be carried out after full recovery or the birth of a child. If available absolute contraindications, diagnostics should be changed to a highly informative, as well as safe blood test.

Kinds

To date, there are several types of skin tests:

  • scarification. The doctor in a small amount applies a concentrated irritant to the forearm of an allergic person, after which he makes short scratches with a lancet or a needle;
  • application. This type of skin test does not imply the need to injure the epidermis. A swab is applied to the patient's skin, previously moistened in a concentrated solution of the irritant;
  • prick test. A drop of the allergen is applied to the patient's skin, after which the doctor makes a puncture with a special needle.

How to prepare for the analysis?

How are allergy skin tests done? In order for the results of the analysis to be extremely accurate, the patient needs to properly prepare before conducting the study. Experts recommend taking several tests before taking skin samples, or rather biochemical and clinical analysis blood, coprogram, general analysis urine.

Besides, in without fail ten days before the planned date of the study, the allergic person must refuse to take any drugs that distort the result. These medications include antidepressants, antihistamines etc.

results

The results of skin tests can be considered negative if the skin after applying a concentrated irritant did not react in any way. However, the answer can also be considered a false negative if there are no skin manifestations at all. In this case, it is recommended to repeat the study.

If, upon contact with the allergen, the skin itches, reddens or swells, the test result can be considered positive. The response to the stimulus can appear both after a few hours and after a few days. The diagnosis also directly depends on the intensity of the reaction.

A mild result is considered questionable if the mild response does not match the symptoms. In this case, the study must be confirmed for this purpose, provocative tests or testing of blood serum are carried out. If available clinical symptoms as a result of the analysis, antibodies will be detected in the serum, the reaction of skin tests becomes positive. Most often, erroneous answers are given by tests if they are not properly prepared for them.

To eliminate the possibility of error, doctors often apply pure histamine to the epidermis before the test, and only then a drop of the irritant. If the skin reacts to histamine with redness, but does not react to the allergen at all, the answer can be considered unmistakable.

Statistics show that every tenth allergy sufferer receives inaccurate results after a skin test.

Side effects

Skin tests for allergies in children and adults, like any other medical manipulation, can cause side effects, which include swelling, redness, itching, rashes, blisters, and so on.

These symptoms in most cases disappear within a few hours after the test, but sometimes they can persist for up to two or three days. To get rid of unwanted side effects, it is enough to use ointments that contain cortisone.

As a rule, compliance with the rules for conducting the test, as well as preparing for it, allows you to completely avoid side effects. This is especially true of the moment associated with an exacerbation of the disease. Therefore, it is strictly forbidden to conduct a study when allergic symptoms are pronounced.

Price

Allergy skin tests can be done at a regular public hospital after seeing an allergist, or at any private clinic. As a rule, the cost of the analysis depends on the number of allergens involved in the study, as well as on the quality of the reagents used.

Extremely rarely, skin tests can cause a serious allergic reaction, which only doctors can eliminate. This kind side effects are, as a rule, immediate, therefore, immediately after the test, the patient must remain under the supervision of doctors for some time.

Diagnosis of allergic diseases is based on the identification of a causal relationship between clinical symptoms and certain factors in combination with positive results of allergy tests (allergy tests). Allergy testing is diagnostic measures to identify allergens - substances to which the body reacts negatively. The solution of this problem is dealt with in the allergology and immunopathology room of the Central Clinical Hospital of the Russian Academy of Sciences.

Indications for an allergy test

  • Frequent nasal congestion, accompanied by discharge, without connection with viral infections;
  • Itching in the nose or in the eyes without visible reasons;
  • Rash on the body;
  • The skin is itchy or swollen;
  • There is sudden shortness of breath, coughing, wheezing, or signs of suffocation;
  • There is a pronounced reaction to insect bites.
    All these manifestations can be caused by allergic reactions:
  1. food allergy;
  2. Allergodermatitis;
  3. drug allergy(particularly on medications, on anesthetics in dental practice, on lidocaine, ultracaine);
  4. hay fever.

Contraindications

    You should refrain from testing in the following cases:
  • The patient accepts antihistamines;
  • With an exacerbation chronic diseases;
  • If the patient has had anaphylactic shock;
  • Pregnant and lactating women, under the ban and the period of menstruation;
  • AIDS;
  • Mental and nervous disorders;
  • Childhood and old age.

    • Types of Allergy Tests

    The technology of conducting allergological tests depends on the type of allergens being studied and the type of allergic reaction. In vivo tests are performed directly on the patient and include:

    Skin allergy tests

    • skin tests
    • intradermal tests
    • application or patch tests

    The method consists in identifying the allergen by applying the drug to the skin and fixing the reaction of the body. The method allows to identify some infectious processes- brucellosis and tuberculosis. An adult (not older than 60 years) can carry out up to 20 samples per day. Children over 3 years old - up to two.

    Skin tests can detect allergies to anesthesia.

    Used for skin testing different groups allergens:

    • Household - dust mites, library dust;
    • Pollen - on the pollen of plants;
    • Meadow grasses;
    • Weed grasses - ambrosia, etc.;
    • Fungi, including molds;
    • Epidermal group: for a specific animal - for a dog, for mice, etc.

    Provocative allergy tests

    If all of the above studies do not give a result, provocative tests are used - the allergen is injected into the site of manifestation of an allergic reaction. Allergy testing is done in a hospital.

    TTEEL by Ado

    Test inhibition of natural emigration of leukocytes. The method consists in counting the number of leukocytes in the liquid before and after washing the oral cavity with a solution containing the drug, an allergy to which is detected. The concentration of the drug is minimal so as not to harm the patient. If the number of leukocytes after rinsing has decreased by more than 30%, this indicates that the patient has intolerance this drug. The method requires additional research.

    Tests to Diagnose Urticaria

    • Laboratory tests blood
    • Swabs from the nasopharynx
    • Study of the intestinal microflora
    • Function Examination thyroid gland
    • Allergy tests (tests for food and household allergens, fungal screening, inhalation screening)

    Tests for the diagnosis of drug allergy.

    used to detect drug allergies different types or a set of tests:

    • Laboratory blood tests
    • Prick testing
    • TTEEL by Ado
    • Sublingual and oral provocation tests

    In each type of test, the biological material of the patient is examined: blood from a vein, serum, sputum, broncho-alveolar washings, etc. Modern methods laboratory diagnostics include:

    • detection of specific class E immunoglobulins to various protein allergens ELISA method,
    • ImmunoCAP and ISAC,
    • in some cases, it is informative to determine the level total immunoglobulin class E in serum.

    In vitro tests are laboratory research sensitivity of the body to the allergen. The biological material of the patient is examined: blood, serum, sputum, broncho-alveolar washings, etc. Modern laboratory diagnostic methods include: detection of specific class E immunoglobulins to various protein allergens by ELISA, ImmunoCAP and ISAC, in some cases it is informative to determine the level of total class E immunoglobulin in the blood serum.

    For diagnostics atopic diseases(asthma, rhinitis, atopic dermatitis, conjunctivitis, allergies to insect venom) skin prick, scarification (scratches) and intradermal tests are carried out, determination of the level of specific IgE to the corresponding allergens.

    If you suspect a respiratory allergy ( allergic rhinitis, asthma) skin allergy tests - prick tests serve as a first-line diagnostic test. Determination of specific IgE levels and provocative tests are necessary for unclear diagnosis and sensitization to many allergens.

    The main advantage of laboratory tests is the fact that their information content is not affected by any stage allergic disease, neither the condition of the patient's skin, nor the drugs taken at the time of the study.

    For the diagnosis of delayed and delayed hypersensitivity reactions (allergic contact dermatitis, toxicoderma), application and intradermal tests, provocative tests are performed.

    Where to take allergy tests?

    Sign up for a consultation with an allergist-immunologist at the Central Clinical Hospital of the Russian Academy of Sciences in Moscow, where you can submit a biomaterial and get a transcript of the results within one day. We invite patients who suffer from allergies or just want to make sure there is no reaction to certain medications, such as antibiotics or anesthesia before surgical intervention. We do allergy tests quickly, accurately, and at affordable prices. An appointment with an allergist is made by phone or online. How much it costs to take an allergy test of the type you need is indicated in the price list of the clinic.

    Cost for certain types of samples

    Name of service Price

    Cutaneous investigations of reaction to allergens (atopic inhalant allergens)

    		 2000

    Skin tests for allergens (additional tests to clarify sensitization to atopic allergens)»

    		 1200

    Skin tests for allergens (extended spectrum of atopic inhaled allergens)»

    		 2800

    Intradermal studies of reactions to allergens (household, epidermal, fungal, food)

    		 1600

    Intradermal studies of reaction to allergens (test with autoserum)

    		 2000

    Skin Allergy Application Testing

    		 6900

    The study of specific Ig E to antigens plant origin: panel of grass allergens (urchin team, meadow fescue, perennial rye, timothy grass, meadow bluegrass)

    		 1100

    Study of specific Ig E to food antigens: crackling

    		 500

    The study of specific Ig E to food antigens: Wheat flour

    		 500

    Investigation of specific Ig E to food antigens: peanut

    		 500

    The study of specific Ig E to food antigens: soya beans

    		 500

    Study of specific Ig E to food antigens: hazelnut

    		 500

    Study of specific Ig E to food antigens: crabs

    		 500

    Study of specific Ig E to food antigens: shrimp

    		 500

    Study of specific Ig E to food antigens: tomatoes

    		 500

    Study of specific Ig E to food antigens: carrots

    		 500

    Examination of specific Ig E to food antigens: egg yolk

    		 500

    The study of specific Ig E to antigens of plant origin: a panel of grass allergens (spiky spikelet, perennial rye, cultivated, woolly boule, timothy, rye)

    		 1100

    Study of specific Ig E to food antigens: celery

    		 500

The essence of an allergy test is direct contact between the body cell and the substance being tested. Thanks to such diagnostics, a person learns how the body reacts to a particular stimulus. With the help of this study, the doctor selects necessary treatment from an allergic disease.

Indications for allergy testing are:

  • tendency to allergic reactions;
  • initial administration of anesthesia;
  • extract medical preparations;
  • unidentified irritant reaction of the body;
  • bronchial asthma;
  • respiratory failure;
  • seasonal allergic rhinoconjunctivitis (hay fever);
  • pollen allergy;
  • reaction of the body after the use of the drug;
  • inflammation of the nasal mucosa (rhinitis);
  • inflammation of the skin (dermatitis).

Types of tests

Allergic tests are divided into 2 groups:

  1. Invivo - skin tests performed on a patient with immediate results.
  2. Invitro - tests conducted without the participation of the patient.

The Invitro group includes a blood test for immunoglobulin E (IgE).

The Invivo group includes the following types allergy test:

  • application (skin);
  • scarifying (needle);
  • intradermal (injection);
  • provocative.

A provocative test according to the research method is:

  • nasal;
  • inhalation;
  • conjunctival.

Skin-allergic tests are used to detect:

  • infectious diseases;
  • external allergic stimuli.

Allergy skin tests should be used to diagnose the following infectious diseases:

  • protozoal infection;
  • mycosis;
  • helminthiasis;
  • bacterial infection;
  • viral infection.

External allergic stimuli include:

  • plant pollen;
  • household dust;
  • food products;
  • medicinal and chemical preparations.

Blood test

The most informative and accessible type of allergy testing is a fence venous blood.

The main indicator that is examined in this type of test is immunoglobulin E (IgE). He is responsible for barrier functions organism before external environment. If the immunoglobulin level is exceeded, then the doctor issues a verdict - there is an allergic reaction.

Application (skin)

They are called a patch test and are used to diagnose several human vulnerability factors at once:

  • contact sensitization to drugs;
  • reactions to chemical allergens;
  • body response to metal ions.

Scarifying (needle)

Such samples are also called prick tests and are designed to diagnose:

  • angioedema;
  • atopic dermatitis;
  • seasonal manifestations of allergic reactions.

Intradermal (injectable)

If the allergist believes that the cause that caused the adverse reaction of the body is a fungus or bacteria, then a study is prescribed by the intradermal (injection) testing method.

Provocative tests

In the case when the diagnosis is difficult to establish, and the disease manifests itself as strange reactions of the body, then the patient is prescribed provocative tests. The term for this study was coined by the English physician D. Blakley. He was engaged in setting an allergy test back in 1873.

To date, provocative tests are used to establish or confirm the diagnosis. The essence of testing is that the body is tested with an allergological reagent in conditions that are as close to natural as possible. This means that the reagent is applied not only to the skin, but also instilled into the eyes, nose or inhaled by inhalation.

Preparation for allergy tests

An allergy test will not take much time for the patient, but it is necessary to prepare for the test in 2-3 weeks.

To prepare for a blood test or an allergen test, you need to:

  • eliminate food allergens from the diet;
  • limit contact with pollen allergens;
  • avoid pets;
  • stop smoking at least 2 hours before the procedure;
  • temporarily stop taking antihistamines.

The main thing that a patient who goes to take an allergy test should pay attention to is diet. It is necessary for a while before the study to exclude the list of products that the attending physician will limit.

How are samples made?

During the test, the laboratory assistant has a first aid kit emergency care. Before the test, the allergy sufferer is consulted about the acceptable reactions of the body, which are considered the norm. Allergy tests in adults are taken after at least three weeks from the moment when the disease has progressed.

Depending on the type, the samples are done like this:

  1. The blood test is taken intravenously.
  2. For an application (skin) test, a body area clean from allergic reactions is selected and a small piece of a bandage or gauze bandage is applied to it, approximately 1 cm2. It is pre-wetted in the reagent and fixed with a non-breathing bandage (adhesive plaster). The reaction time is set individually, and usually ranges from 15 minutes to 2 days.
  3. A clean area of ​​skin is prepared for a scarification (needle) test. Light scratches are applied to it with a scarifier or a needle. Reagents are applied to the resulting wound by the drip method. The result of the reaction will come a day after the test. The area to be examined must be protected from water and cosmetics.
  4. To conduct an intradermal (injection) test on clean skin, with a depth of not more than 1 mm, an injection with a reagent in the form of a button with a diameter of not more than 5 mm is injected with an injection. A bubble forms on the skin white color, which should dissolve within 15 minutes.
  5. Nasal allergy tests are taken in case of inflammation of the nasal mucosa, as well as with a runny nose and sneezing. The reagent is alternately instilled into each nostril and the reaction of the body is carefully observed.
  6. During the inhalation test, it is necessary to inhale the reagent in the form of an aerosol. The medical worker will monitor the reaction of the body, namely respiratory system. If necessary, the procedure is repeated after an hour, and the concentration of the reagent in the aerosol can also be increased.
  7. A conjunctival test for diagnosis is carried out in front of the eyes by instilling a liquid with a reagent into them. The waiting time for the reaction is maintained individually. To ensure the accuracy of the result, medical worker may repeat the allergy test by increasing the dose.

The video shows how allergy tests are done and how the result is interpreted. Filmed by Elena Malysheva channel.

Can children be tested for allergens?

Despite the concern of many parents, children can. Of course, provided that the baby is over 5 years old and there are good reasons for such a study.

Indications for allergy testing in children:

  • anaphylactic shock;
  • negative reaction to the vaccine;
  • reaction to the product
  • response to an unknown external stimulus.

Tests for allergens in children do not differ from an adult allergy test. The only exception is the fact that a minor patient will not be taken provocative tests for allergens.

Research results

The interpretation of the results depends on the type of allergy test:

  1. In a skin examination, the human body, predisposed to allergic reactions, will react to allergy tests within a day. At the sample site with a positive result redness or blistering occurs. Thus, the laboratory assistant will be able to determine which allergen has manifested itself to a greater or lesser extent on the skin or in the body.
  2. When analyzing blood for a specific allergen, the patient is given a result that determines the reaction to a particular irritant. Opposite each item is one of possible reactions: negative, positive or doubtful (weakly positive).
  3. Deciphering the results of a blood test for immunoglobulin is carried out by medical professionals.

The table of norms for the value of total IgE is shown in the photo.

Contraindications

Allergy testing is contraindicated for:

  • pregnancy;
  • breastfeeding (lactation);
  • high degree of development of the disease;
  • exacerbation of neuropsychiatric diseases;
  • menstruation;
  • the use of contraceptive, hormonal and sedative drugs;
  • diabetes;
  • AIDS;
  • oncology or suspicion of the presence of malignant tumors;
  • increased body temperature;
  • the use of medications, the use of which cannot be canceled;
  • infectious and viral diseases;
  • age over 60 years.

As a rule, the patient is not allowed to take an allergy test for colds, acute respiratory infections or SARS. To obtain reliable results allergy test, the doctor excludes any ailments of the body that may affect the change in test readings.

Complications and consequences

Allergy testing is not only a way to learn about external stimuli, but also a rather risky experiment on the body. Therefore, such studies are carried out only in medical institution and trained professionals capable of providing first aid if necessary.

Complications and consequences of an allergy test:

  • angioedema;
  • anaphylactic shock;
  • fatal outcome.

If the patient complies with the doctor's instructions before visiting treatment room for an allergy test, there are usually no complications after the test.

cases anaphylactic shock or death are single and are of an individual nature, due to acute intolerance or negligence of a medical worker.

Where are the tests carried out and how much does the study cost?

Allergy testing can be done state polyclinic, after referral by an allergist. The study is also carried out in private diagnostic centers.

Allergy tests- this is one of the most highly informative methods for determining personal intolerance by the human body of various kinds of chemical irritants (allergens).

This method is the most effective, with minimal discomfort for the patient.

Allergic diagnostic tests are carried out only after complete examination sick.

Indications for an allergy test

  • allergic dermatitis and;
  • seasonal or chronic runny nose ();
  • (runny nose, discharge of mucus from the nose);
  • (itching, dry skin);
  • swelling and swelling of the skin, shortness of breath;
  • unreasonable itching in the eyes, eyelids, nose;
  • diarrhea;
  • pain and cramps in the stomach;
  • reactions to animal or insect bites (for example:);
  • sensitivity of the body to household chemicals and medicines.

All or some of the above symptoms present in a person require a full examination to verify the presence of an allergy. best method is an allergy test.

The purpose of an allergy test is:

  • determination of the method of treatment of allergies;
  • testing of reintroduced drugs;
  • establishing a reaction to cosmetics, food, animals, insects, dust, etc.

Allergy occurs due to the body's reaction to an irritating factor, which means that the immune system violated. Allergotest will help to identify the main pathogens, thereby preventing subsequent reactions of the body.

By identifying allergens, a person will know what to avoid (food, household chemicals, cosmetics, dust, etc.).

Contraindications for allergy testing

Like many other methods, allergy testing can be contraindicated for a person. This happens in cases where:

  • man is sick infectious diseases With chronic course( , pneumonia, );
  • a person has acquired immunodeficiency syndrome (AIDS) or others, in which an allergotest is prohibited;
  • (anaphylactic and anaphylactoid reactions);
  • when breastfeeding (lactation);
  • asthmatic bronchitis at the decompensated stage;
  • bearing a child;
  • worsening of allergic reactions;
  • mental disorders (neurosis, neurasthenia, schizophrenia, etc.).

There are two types of restrictions for conducting an allergic test: absolute and relative.

  • Absolute imply another safe and highly informative for the presence of antibodies ().
  • With regards to relative contraindications, then during pregnancy, pneumonia and tonsillitis, the introduction of even the smallest dose of an allergy causative agent is prohibited.

Allergy tests for children are also contraindicated if they have a sore throat, a cold, etc.

Types of allergy tests

To identify the main allergens, allergists use several types of tests. Types of allergy tests:

  • Allergy scarification tests. This allergy test is carried out to determine the sensitivity human body to various pathogens of allergies;
  • Application. It implies the introduction of an allergen fragment under the skin, after which local skin changes are observed and evaluated;
  • Prick test or prick. The most convenient and fastest test for detecting allergic reactions;
  • Direct. An examination is done to diagnose diseases that have developed with intolerance to a particular irritant. The epidermis and the suspected allergen are in direct contact;
  • Indirect. These allergy tests are quite laborious and time consuming. During the test, it is necessary to be under the strict supervision of a specialist. Also, the method is painful, since allergens are injected deep under the skin.
  • Provocative. The method is used only if other methods gave low information content. A provocative test makes it possible to establish a diagnosis more accurately than previous tests.
  • Cytotest. A cytotest is used to detect food allergies. Rash, dry skin and itching can be caused by a malfunction gastrointestinal tract. This allergy test involves checking reactions to 50 or more foods that can be eaten daily. This method recommended for people who have underweight or overweight, itchy rash, general malaise, stool disorder (diarrhea, constipation).

Holding certain types testing involves the inclusion of the top layer of the skin in the process.

Skin allergy tests are the most informative for clarifying the diagnosis, diagnosing allergic diseases or the type of allergen.

What types of allergy tests to conduct is determined by the allergist in order to obtain accurate results in the future.

Allergy testing in children

Children who have any of the relatives prone to allergic reactions also need to be diagnosed.

It happens that despite proper diet nutrition and care, the child still manifests allergic reactions. Neither parents nor doctors can accurately determine what an allergy is. It is in this case that allergy tests can achieve the best result.

To understand how children are tested, it is necessary to consult with an allergist before the procedure.

The most suitable allergy tests for children are scarification, that is, on skin apply the irritant in a certain amount. The scarification view is usually carried out on the forearm, children on the thigh or back.

The method is done in three ways:

  • scratches upper layer epidermis and the allergen is applied;
  • piercing the skin with a special needle;
  • intradermal test - the allergen is injected with a syringe.

Allergy skin tests involve the observation by specialists of the body's reaction to an irritant. The brighter in color and larger the spot that forms around the sample site (prick or scratch), the more likely it is to make a correct diagnosis and identify the underlying pathogen.

Samples are not allowed for all children. Allergy tests for children under two years of age do not give the expected result and cause discomfort.

Also, in order to test for allergies to children, the disease must be in the stage complete remission, that is, the child during this period should not have a single sign of illness (rash, runny nose, cough, etc.).

Adults should not give the child any anti-allergic medicines before conducting an allergic test.

Preparation before an allergy test

A specialist will help you prepare for the procedure, explain and give certain recommendations.

Eating before allergy testing is not prohibited, but on the contrary, it should be mandatory. This is especially true for children.

Using hormonal ointments or creams should be reported to the doctor. V this case the test will be carried out on an area of ​​​​skin that has not been affected by the means.

Before conducting allergic tests, the patient must donate blood for analysis. If the allergy is not identified and there are no obvious contraindications, then you can proceed to the choice of allergy tests.

A blood test is required in order to find out if there is an allergy and to see the amount of components in the blood. You need to be well prepared for the allergy test. A few days before the test, it is recommended to exclude physical and emotional stress.

How are allergy tests performed?

  • Allergy scratch tests. Allergen fragments are applied to the patient's forearm. Several small scratches are made with a needle or lancet;
  • Application. The safest kind. Carrying out does not require any damage to the skin. A swab moistened with an irritant solution is applied to the skin;
  • Prick test or prick. A drop of the allergen is dripped onto the skin, after which the testing area is carefully pierced with a special medical needle;
  • Indirect. First, an allergen is injected under the skin, after a while the doctor collects venous blood to determine the level of antibodies;
  • provocative. The Praustnitz-Küstner reaction is performed, that is, serum with the blood of an allergy patient is injected healthy person, by blood microscopic examination identified particles of the alleged allergen. A day later, the doctor determines the level of all antibodies in the skin, after which the area where the test was performed is treated with an allergen. Next comes the standard observation of the body's response to the stimulus.

Evaluation of scarification skin tests

Reaction Result Characteristic
negative– Absence of swelling and hyperemia
Doubtful± Hyperemia without swelling at the test site
Weakly positive+ Swelling reaches 2-3 mm, noticeable only if the skin is stretched, severe hyperemia
Positive+ + Swelling reaches 4-5 mm, noticeable without stretching, high hyperemia
Strongly positive+ + + Swelling reaches 6-10 mm with the presence of pseudopodia, high hyperemia
very strongly positive+ + + + Swelling reaches more than 10 mm with the presence of pseudopodia, severe hyperemia and lymphangitis

Evaluation of intradermal allergy tests

Reaction Result Reaction characteristic
negative– The dimensions are the same as in the control
Doubtful± Swelling resolves much more passively than in control
Weakly positive+ The swelling is 4-8 mm in diameter, the skin around is hyperemic
Positive medium degree+ + Swelling reaches 8-15 mm in diameter, skin hyperemia
Strongly positive+ + + Swelling reaches 15-20 mm in diameter with the presence of pseudopodia, skin hyperemia
very strongly positive+ + + + Swelling more than 20 mm in diameter with the presence of pseudopodia, cumulative blisters around the circumference with severe hyperemia of the skin

Deciphering the results of allergy tests

One of the most informative and quick tests is the prick test. The applied scratches and the action of the allergen will give an accurate result about the presence or absence of allergic reactions.

The main indicator is the width of the scratch or puncture site.

If the scratch is no more than 2 mm, then the reaction is negative, if 5 mm - positive (see photo above). General transcript analysis takes no more than five minutes. After that, the specialist explains the results of the diagnosis to the allergy sufferer himself or to the parents of the sick child.

To date, each person can guess the presence of allergies. Symptoms are pronounced, therefore, at the first unreasonable signs, it is necessary to contact an allergist and an immunologist. This is especially true for children, as Small child tolerates allergy symptoms worse than an adult.

To know what needs to be excluded from the diet or to avoid any other irritating factors, an allergic diagnostic test should be done.

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