General blood test for diagnosing allergies: norm and pathology

Why specifically a blood test for allergens?

When diagnosing allergies, a blood test has advantages over skin (scarification) tests:

— there is no need for the patient’s skin to come into contact specifically with the allergen and, as a result, the possibility of an acute allergic reaction is excluded;

- a blood test can be done at any time, while skin tests are prohibited during periods of exacerbation of allergies;

— one blood draw is sufficient to test for an unlimited number of allergens;

— the result of a blood test for allergens contains both a quantitative and an objective indicator, which makes it possible to assess the degree of sensitivity to each allergen.

There are times when it is impossible to conduct skin tests, and then a blood test is indispensable.

Indications for which only a blood test for allergens is prescribed:

- significant damage to the skin (for example, the patient has eczema or atopic dermatitis);

- excessive allergic skin reaction - can give a false positive or false negative result (for example, with Quincke's edema, recurrent urticaria, mastocytosis);

- constant or frequent use of antiallergic drugs by the patient, as a result of which the sensitivity of the skin to allergens decreases;

- a history of an anaphylactic reaction or if there is a possibility of its development;

- the need to diagnose allergies in children or the elderly - a skin test in this category of patients for us may not be informative due to the modified degree of response to irritants.

Determination of IgE in blood

Total IgE is the antibody that is responsible for causing allergies.

A blood test to determine this indicator is used if skin tests do not provide an unambiguous result or cannot be done due to contraindications.

The main indications for this analysis include:

Allergic diseases – bronchial asthma, hay fever, atopic dermatitis, food and drug allergies, eczema.
Helminthiasis is a pathology caused by parasitic worms.
Assessment of the threat of allergies in children whose relatives have allergopathy.

Photo: Kit for determining IgE in blood

Preparation for the study and how it is carried out

Three days before the analysis, you need to exclude any physical and emotional stress.

To conduct the study, blood is taken from a vein.

This analysis does not require patient contact with allergens and is therefore absolutely safe.

However, it is slightly more expensive than skin testing and takes several days to complete.

Contraindications

This analysis has no contraindications - it can be performed even during an exacerbation of the disease and can be done for children under three years of age.

However, practice shows that this study should not be carried out on babies under six months of age.

At this age, the immune response is too weak, and therefore the IgE level is still low.

What are allergens?

All allergens are divided into groups depending on their origin:

Food allergens are food products: eggs, milk, citrus fruits, nuts, seafood, meat, yeast, mushrooms, oil, seasonings, flour and so on.

First, the allergist orders a blood test for allergens from the main group of food products (about 90 items). If the analysis does not give any result, then the doctor may order an extended blood test, including the most food allergens.

2. Allergens of animal origin: saliva and fur of domestic animals (dogs, cats, rodents), down of poultry, chitinous cover of cockroaches, insects, “live” food for fish (bloodworms, daphnia).

3. Allergens of plant origin - pollen of blooming grasses and trees, poplar fluff.

4. Household allergens: house dust, feathers and fluff from blankets and pillows, mites, mold fungi in damp places.

For example, dust mites can stimulate bronchial asthma. If a person feels lethargic after sleeping or relaxing in his own apartment, and he does not have pets or blooming plants, or he notices allergy symptoms, then he should immediately consult a doctor so as not to trigger the disease and avoid complications.

5. Pharmaceutical allergens: most often, an allergic reaction is caused by taking medications (ampicillin, penicillin, amoxicillin) or insulin (bovine, porcine, human). But it is worth understanding that any pharmaceutical product can cause an allergic reaction.

Allergochip, analysis for 112 allergens

An immunological blood test allows you to accurately determine the allergen to which a particular person develops an allergy.

It is best to determine a specific allergen using a comprehensive blood test called Allergochip.
This examination allows you to determine whether the body is sensitized to any of the 112 most common allergens.
However, you only need to donate blood once.
For example, “Allergochip” (synonymous with ImmunoCAP) allows you to identify both food allergens (fruits, vegetables, nuts) and others: pollen of various plants, cow’s milk, eggs and others.
A total of 112 different allergens will be shown.

How to take a blood test correctly

To take a blood test for allergens, no special preparation is required. It is enough to adhere to general advice when donating blood for analysis:

- 3 days before blood sampling, refrain from physical and sensory stress;

- do not drink alcohol the day before the test;

- do not smoke an hour before the procedure;

- undergo the test early in the morning and on an empty stomach, although some diagnostic laboratories take blood for analysis hours after eating.

Features of preparation for testing

The bulk of allergy testing involves drawing blood from a vein, and this procedure requires some preparation. Thanks to high-quality preparation, you can be confident that the final results will be informative and reliable.

Donating blood from a vein requires compliance with the following rules:

A blood test for allergens is performed during the period of remission of the pathology, since during an exacerbation of the allergic reaction the number of antibodies increases significantly, which gives inaccurate results.
It is prohibited to donate blood for viral and infectious diseases that are characterized by an increase in body temperature.
3-4 days before donating blood, it is recommended to stop using any medications.
5 days before blood collection, you should reduce the frequency of contact with pets and exclude food products that provoke an allergic reaction from your diet.
Before taking a blood test for allergens, it is strictly forbidden to exercise, smoke, or drink coffee drinks.
Blood sampling is carried out in the morning on an empty stomach. When testing blood for allergens in infants, blood sampling should be carried out no less than 3 hours after the last meal.

Deciphering a blood test for allergens

A blood test for allergens takes from 3 to 7 days.

Let's look at the reference values for the result of a blood test for allergies.

General IgE is an immunoglobulin that is normally found in the blood in insignificant quantities. In people with allergies, there is an increase in IgE levels. The more contacts with the allergen, the higher the concentration of IgE in the blood.

Normal IgE levels vary depending on a person's age:

— in newborns (up to 2 years) – mIU/ml;

— children from 2 to 14 years old – mIU/ml;

— children over 14 years old – mIU/ml;

— adults under 60 years old – mIU/ml;

— adults over 60 years old – mIU/ml.

IgG (IgG4) is a specific immunoglobulin used to identify the allergen in food allergies.

Reference values:

< ng/ml – the product can be eaten;

– ng/ml – the product can be eaten no more often than once a week, observing product rotation;

> ng/ml – you should avoid consuming this product for 3 months.

The final diagnosis must be made by an allergist, giving a breakdown of the blood test for allergens.

+-➤ Blood test for allergies and allergensClick to collapse

+-➤ Allergy tests: types and panel of allergensClick to collapse

An allergy blood test is a clinical test that allows you to identify allergens that provoke an allergic reaction in a person.

During this test, a specialist describes the presence in a person’s blood of allergen-specific antibodies to various allergens.

Individuals suffering from diseases such as bronchial asthma, atopic dermatitis, eczema, hay fever, helminthiasis, pharmaceutical and food allergies are required to undergo a blood test for allergens. In addition, patients who have a hereditary predisposition to allergic manifestations should undergo testing. We suggest you consider the individual characteristics of this test.

Detection of specific immunoglobulins

If, using previous tests, it was possible to detect the presence of an allergic reaction and suggest what exactly the allergen is, then a blood test for specific allergens (specific immunoglobulins G and E are detected) will make it possible to accurately determine the source of the allergic reaction.

With this research method, blood is divided into small portions and mixed with a variety of allergens. The number of substances studied can reach 190. Next, doctors study blood samples and determine the immune response. The higher it is, the more dangerous the allergen is for humans.

How to determine an allergen using a blood test if the multiple chemiluminescence method is used for diagnosis? Quite simple, since in this case special panels are used on which allergens are placed. The allergy panel is filled with the patient's blood. If an allergy to a specific substance is present, the presence of specific antibodies can be noted in the blood sample.

There are three types of reactions when testing blood for allergens in adults and children:

low – the substance does not pose any danger;
medium – it is preferable to minimize contact with the allergen; if it is a food product, it is recommended to exclude it from the diet;
high – an allergy is caused by this substance and contact with it must be completely avoided.

The results of a blood test for allergens are presented in the form of a long table, where the patient himself can study which substances are dangerous for him.

What is the advantage of blood testing for allergens compared to skin testing?

As experts say, blood testing has a number of advantages compared to scarification (skin) tests:

there is no need for human skin to come into contact specifically with the allergen and, as a result, the possibility of developing an acute allergic reaction is eliminated;
A blood test can be performed at any time, while skin tests cannot be performed during an exacerbation of allergies;
the result of a blood test for allergens has quantitative and high-quality characteristics, which allows you to assess the level of sensitivity to a specific allergen;
Just one blood draw is enough to study the patient’s body’s reaction to an unlimited number of allergens.

Sometimes situations arise in which it is impossible to perform scratch tests, and then you cannot do without a blood test.

The indications for which a blood test for allergies is prescribed are the following:

significant skin damage (eczema, atopic dermatitis);
a high degree of allergic skin reaction, which can give a false-negative or false-positive result (with recurrent urticaria, Quincke's edema, mastocytosis);
regular or frequent use of antiallergic drugs by a person, as a result of which skin sensitivity to allergens is significantly reduced;
presence in the patient's medical history of an anaphylactic reaction or the possibility of its development;
the need to determine an allergic reaction in children or elderly patients (skin testing in these categories of persons may be uninformative due to the modified degree of response to irritants).

Diagnosis of allergen using skin tests

To detect an allergic reaction, it is enough to perform a general blood test, but in this case it is impossible to directly determine the allergen. That is why such a diagnostic method as skin testing is widely used.

The advantages of the technique are the ease of implementation and research, due to which the patient receives results on the same day. The peculiarity of the procedure is the subcutaneous injection of the allergen. This diagnostic method is absolutely safe, since the amount of the introduced allergen is so small that it cannot have a negative effect on the body.

The results of the allergen test can be seen after just half an hour. Even with a minor allergic reaction, skin redness, swelling, and a rash may occur.

There are 4 types of allergen tests:

subcutaneous;
application;
peak test;
scarification analysis.

The test option is selected by the attending physician, taking into account the age group, symptoms and individual characteristics of the body.

Main types of allergens

All allergens, depending on their origin, are divided into groups:

Food products: eggs, citrus fruits, milk, nuts, meat, seafood, yeast, oil, mushrooms, seasonings, flour and others.
At first, the specialist gives the patient a blood test for allergens from the main group of food products (about 90 possible allergens), and if the study does not produce any results, then he gives a referral for an extended blood test (includes about food products).
Allergens of plant origin - poplar fluff, pollen of flowering trees and grasses.
Allergens of animal origin: hair and saliva of domestic animals (cats, dogs, rodents), chitinous cover of cockroaches, down of poultry, insects, fish food (daphnia, bloodworms).
Medications.
Allergic reactions are mainly caused by medications such as insulin and medications (penicillin, ampicillin, amoxicillin). But it is important to keep in mind that any medication can provoke an allergic reaction.
Household allergens: feather and down from pillows and blankets, house dust, mites, mold fungi. For example, dust mites can cause asthma. If a person complains of constant lethargy after resting or sleeping in his own home, and also notices manifestations of allergies, while he does not have blooming plants and pets, he must urgently contact a specialist. This will prevent the disease from progressing and avoid complications.

How to take a blood test correctly?

In order to take a blood test for allergies, the patient does not require special preparation.

It is enough just to follow the general advice when submitting for research.

As a rule, all blood tests are taken on an empty stomach in the morning (hours after eating). It is also recommended from time to time to take a blood test for allergies on an empty stomach, but it is often enough to maintain a 3-hour interval between the last meal and this procedure.

It is important to refrain from physical activity and sensory stress 3 days before the test, and the day before the blood test it is prohibited to drink alcohol and smoke.

Tests in children

There are no big differences in the diagnosis of allergic diseases in children. For research, venous blood is also taken, which is studied using the described methods.

Some features in pediatric practice:

Skin tests are contraindicated in children under 3 years of age.
Up to 6 months, a blood test for immunoglobulin E is not effective, since the mother’s immune proteins that enter the milk circulate in the blood.
To study children over 3 years of age, a special pediatric panel is used, described above.

Find out the results of your child's allergy test in time so as not to expose him to suffering from this disease. Reliable test data allows the doctor to provide appropriate therapy.

Deciphering a blood test for allergens

The blood test for allergens is completed within days.

We suggest looking at the main meanings of allergy test results.

IgE is an immunoglobulin, which is found in small quantities in the body of a healthy person, and in people suffering from allergies, its concentration is slightly increased.

The more contacts a person has with allergens, the higher the level of IgE in the body.

Normal IgE levels vary depending on a person’s age:

in newborns (up to 2 years of age) they are mIU/ml;
in children aged 10 years they are in the spectrum from 0 to mIU/ml;
in patients over 14 years old – mIU/ml;
in adults under 60 years old – mIU/ml;
in adults over 60 years of age they are mIU/ml.

IgG (IgG4) is a specific immunoglobulin that is used to identify the allergen in food allergies.

Let's consider the reference values of this indicator:

< ng/ml – the product is allowed for human consumption;
– ng/ml – the patient can use the product, but not more than 1 - 2 times a week;
> ng/ml – a person should avoid consuming a certain product for 3 months.

Having deciphered the blood test for allergens, the specialist will be able to make a final diagnosis and prescribe the correct treatment for the patient.

The number of allergy sufferers is increasing every year. More and more often, different types of allergies can be observed in children from a very early age. For this reason, tests for allergic reactions are becoming increasingly necessary. Allergies can appear at any age and completely unexpectedly. To protect yourself from allergens. provoking a reaction, it is necessary to accurately find all possible allergens.

Determination of immunoglobulin IgE

Determination of total immunoglobulin.
Calculation of specific immunoglobulin.

What is immunoglobulin? Immunoglobulin is an antibody produced by cells in the body. Their function is to detect and neutralize foreign cells that enter the human body in various ways. The manifestation of allergies depends on these antibodies. Immunoglobulin is produced through lymphocytes and tissue fluid. It can be found in secretions produced by the mucous membrane.

The IgE antibody is responsible for allergic reactions. It functions in the blood for up to 3 days. In the membranes of basophils and mast cells, this antibody functions for two weeks. It is most often localized on the cells of the mucous membranes and epidermis. Even a slight increase in IgE indicates an allergic reaction.

if the immunoglobulin level is insignificant, the body’s condition is considered normal;
if antigens attach, the body releases histamine and serotonin. As a result of these processes, various rashes are observed, itching appears;
Excess IgE indicates the body's tendency to allergic diseases.

An immunogram in children is considered more informative than in adults . A blood test is very convenient to determine the presence of allergies because the patient does not need to come into direct contact with the allergen. Experts consider this method of analytical research to be very effective. It is widely used all over the world due to the lack of contraindications. It can be used even with severe, acute allergies.

IgE testing is carried out for the following indications:

All types and forms of allergies.
Assessment of the likelihood of developing allergies in the presence of a hereditary history.
Helminths.

The procedure is carried out subject to the following rules:

Elimination of physical activity and stress.
Carrying out the procedure on an empty stomach.
The day before the test, you must adhere to a gentle diet. You should definitely exclude strong tea, coffee, and alcohol.

Appointment for tests for allergies

Runny nose, watery eyes, itchy nose and sneezing are signs of allergies.

An allergy is an unusual reaction of the body to certain provoking causes.

It occurs in the event of a malfunction of the immune system, when a person’s immune system recognizes things that are completely safe for him as hostile (pollen, dust, food products, etc.).

Allergic reactions can be quite strong and varied. They depend on the personal characteristics of the body, but never appear once or after a minute of contact with the allergen.

Allergy tests are routinely performed in a comprehensive manner. A single text will not provide complete information about the entire range of possible allergens.

The only method of treating allergies is limiting contact with allergens.

Even antihistamines may not be effective enough if contact with the allergen continues.

If you suspect that you or your baby have an allergy, you need to visit an allergist and get tested.

There are a number of relevant signs of allergies. They can manifest themselves with varying intensities and in different combinations:

Allergic dermatitis.
It occurs when the allergen comes into prolonged contact with the skin. For example, if the cream contains an allergen, the reaction will not appear immediately after its first application, this makes it difficult to find the allergen. Dermatitis manifests itself in the form of a rash, redness of the skin, itching, liquid blisters, spots.
Hives. Hives can occur due to contact or food allergies. In this case, spots similar to a burn appear on the skin; they can quickly spread and unite, which provokes an increase in body temperature.
Allergic rhinitis.
Rhinitis occurs when the nasal mucosa comes into contact with an allergen (animal hair, dust, plant pollen). Allergic rhinitis is accompanied by copious mucus secretion, sneezing, and severe swelling. With seasonal allergies, it can last more than a month.
Allergic conjunctivitis. It is also a common occurrence with seasonal allergies, when the allergen is in the air and reaches the mucous membrane of the eye. At the same time, the eyes begin to water, turn red, itch, there is a feeling of sand in the eyes, and the eyelids swell.

There are other signs of allergy: shortness of breath, cough, lacrimation, diarrhea, vomiting, Quincke's edema. It is often impossible to find reactions without the help of others without special tests.

Diagnostics

If a person discovers allergy symptoms, he should definitely consult an allergist.

The specialist will issue a referral for tests and conduct tests to confirm the diagnosis. Treatment is prescribed to each patient individually.

Survey objectives:

Determine the nature of the disease - allergic or non-allergic;
Determine the degree of involvement of immune/non-immune mechanisms;
Find out the specific cause of the disease.

Diagnostic methods:

Collecting anamnesis and establishing a connection between the development of the disease and exposure to the allergen;
Laboratory tests of blood, urine, feces, sputum from the bronchi, nasal discharge, eyes;
Immuno-laboratory blood test;
Skin tests - drop, patch, scarification, prick test, intradermal test;
Provocative tests - conjunctival, nasal, inhalation, sublingual, elimination;
Instrumental - radiography of the sinuses, bronchi, ECG, ultrasound of the abdominal organs, endoscopy.

When making a diagnosis, the main role is given to collecting anamnesis and identifying the clinical manifestations of the disease. Laboratory and instrumental methods help clarify the doctor’s assumption.

A specific research method is selected for each patient. It depends on the symptoms of the disease. After receiving the results of the examination, treatment and diet are selected for the patient, and recommendations are given on how to avoid repeated attacks of the disease.

General blood analysis

A general blood test is performed if an allergy is suspected. Blood is taken from a finger or from a vein. The analysis has no contraindications; it can be performed on all patients of all age groups.

The study is carried out in the morning on an empty stomach. Before taking the test, you should not eat or drink water for 8 hours.

The following indicators are studied:

Leukocytes;
Hemoglobin;
Red blood cells;
Hematocrit;
Basophils;
Color indicator.

With allergies, changes occur in the number of a subtype of leukocytes - eosinophils. Their number increases by 5%. In case of allergies, the number of basophils in the blood may also increase. When an antigen enters the body, their quantity is higher than normal and amounts to more than 0.2*109/l.

However, sometimes the number of eosinophils increases in the presence of helminths, tumors, rheumatoid arthritis and other pathologies in the body.

Sputum examination

Sputum examination is prescribed if bronchial asthma of an allergic nature is suspected.

Key Features:

Mucus can be collected after a person rinses their mouth and brushes their teeth;
The procedure is carried out during a coughing attack at home or in a clinic;
Avoid getting saliva into biomaterial for laboratory research;
Sputum collection is carried out in the morning on an empty stomach , 8 hours before the test you need to drink as much liquid as possible to facilitate the passage of mucus.

The study is carried out on people of all age groups. The main condition is to be able to cough up mucus from the bronchi.

Indicators that are assessed:

Transparency;
Smell;
Color;
Quantity;
The presence of impurities of pus and blood.

Sputum due to allergies is usually colorless and odorless. It acquires a yellowish or amber tint due to the breakdown of eosinophils. The nature of the sputum is mucous.

Cellular elements that are studied:

Eosinophils;
Red blood cells;
Lymphocytes;
Neutrophils;
Monocytes;
Epithelium;
Macrophages.

An increased number of eosinophils indicates the allergic nature of the disease. In case of allergies, Charcot-Leyden crystals and Courshman spirals are also observed in sputum.

Cytology of nasal secretions

To identify the nature of the disease, nasal mucus taken from the nasal cavity is examined. Using a cotton swab, the secretion is applied to a glass slide and examined under a microscope.

The following indicators are assessed:

Red blood cells;
Neutrophils;
Eosinophils;
Basophils;
Lymphocytes.

With allergies, the number of eosinophils increases by more than 10% . In parallel, the level of basophils and mast cells increases. Leukocytosis is observed.

Tests are carried out in a clinic setting for patients of any age. This method has no contraindications.

To avoid distorting the results, you should stop using nasal sprays and vasoconstrictor drops 12 hours before the test. The nose is not washed or rinsed before the analysis.

Skin tests

If an allergy is suspected, skin tests are performed. After a few hours, the results are displayed. The procedure identifies the cause of the disease and the specific allergen that caused the painful reaction.

As a rule, the test is carried out on the upper back, abdomen, and the inner surface of the forearm from the hand to the shoulder.

Key Features:

Allergens are applied to the skin area . In places where they come into contact with the skin, punctures, scratches or cuts are made;
Sometimes the reagent is applied inside the skin . The essence of the method is that a small amount of various allergens is injected into the skin and a response from the body is awaited;
If swelling or redness appears after 15-25 minutes, the test is considered positive;
You are allowed to do up to 20 tests in one session.

Types of skin tests:

Application - the allergen is a medicine, a small piece of bandage is moistened with a diluted solution and applied to the skin of the arms, back or abdomen, cellophane is applied on top, after 30-60 minutes the results are assessed;
Scarification - different allergens are applied drop by drop to the inner surface of the hand at a distance of 20 mm from each other, scratches are made with a needle, but so as not to damage the capillaries, the condition is assessed after 25 minutes, the test reveals only the reagin type of allergy (hay fever, asthma, rhinitis , Quincke's edema);
Prick tests - a healthcare worker applies a drop of irritant to the skin, then using a special needle carefully pierces the testing area;
The Praustnitz-Küstner reaction is used to determine the reagin subtype of allergic reactions, in which a healthy person is injected intradermally with the blood serum of a sick patient, then the allergen is injected into the same area, and the result is assessed after 25 minutes; the test is rarely used due to the likelihood of infectious contamination.

Applique

Scarification

Prick test

Praustnitz-Küstner reaction
Preparation for skin testing:

Stop taking antihistamines , tranquilizers, antidepressants, glucocorticoids several days before the test;
Calm down and relax before the procedure;
The puncture or scratch site is pre-treated with alcohol.

Methods for performing skin testing:

Epicutaneous - the allergen is applied to the skin surface;
Percutaneous - the reagent is introduced through the surface of the skin by puncturing, scratching or incising it;
Intracutaneous - the allergen is injected into the upper layer of the skin.

Indications for testing:

When bitten by insects;
Asthma;
Rhinitis;
Conjunctivitis;
Skin rash, redness, itching, swelling;
Digestive system disorder;
The appearance of itching and hives after taking medications.

Contraindications for testing:

Ages up to 3 and after 60 years;
Weakened immunity;
Skin diseases;
Period of exacerbation of allergic disease;
Pregnancy;
Exacerbation of other chronic diseases;
Mental disorders;
Respiratory diseases;
The likelihood of a severe reaction to the allergen;
Flowering period of plants.

Allergens included in the research list:

Pollen from flowering plants;
House dust;
Animal wool;
Bird fluff;
Food allergens;
Bacteria or fungi;
Chemicals and medicines.

If the reaction is positive, redness or swelling appears a few minutes after the test. The swelling should grow within 20 minutes. If its size is larger than normal, the allergen has been identified.

Provocation tests

If doctors are unable to determine the cause of the disease, provocative tests are used. The essence of “provocation” is that the allergen is applied to the mucous membrane of the target organ affected by the allergy.

An allergen introduced in this way can give a strong reaction, so the procedure is carried out in a clinic under the supervision of an allergist-immunologist.

Standard medicinal allergens approved for use in tests:

From pollen;
House dust;
Epidermis of animals;
from bird down;
Food;
Bacterial;
Insect.

Indications:

State of remission of an allergic disease;
If skin tests are unsuccessful;
If other studies do not make it possible to determine the allergen;
To specify a food or pollen allergen.

Contraindications:

Exacerbation of allergies;
Acute phase of asthma or infectious disease;
Pregnancy;
Mental illnesses;
AIDS;
Malignant tumor;
There is a possibility of a strong backlash.

Strict restrictions on holding:

Age up to 5 years;
Weakened immunity.

Preparation for the event:

Avoid taking antihistamines 48 hours before
Stop using glucocorticosteroids within 2 weeks

Types of provocative tests:

Nasal – used for rhinitis of an allergic nature. A control liquid is prepared for the sample. It is diluted tenfold. Before the procedure, the patient's nasal breathing is assessed and rhinoscopy is performed. The control liquid is instilled into only one nostril. The patient is monitored for 10 minutes. If there is no reaction, a more concentrated solution is instilled into the other nostril. The interval between instillations should be 20-30 minutes. If symptoms of rhinitis appear, the test is considered positive;
Conjunctival - used to study conjunctivitis of the eyes due to hay fever or reaction to dust. The control fluid is instilled into the lower conjunctival sac. If there is no reaction, then after 30 minutes a test is performed on the other eye. Testing is considered positive if symptoms of conjunctivitis appear;
Inhalation – used to study bronchial asthma. They use household, epidermal, pollen, and bacterial allergens. First, the patient's respiratory functions are checked. Then, using a jet inhaler, a control drug is injected into the bronchi. After 20-40 minutes, a person may develop a cough and shortness of breath. This reaction is considered positive. The person must be under medical supervision for 24 hours. During the day, you can use only one allergen for inhalation;
Sublingual - used to study food or drug allergies. Before testing, a person's blood pressure and heart rate are measured. The control drug is placed under the tongue for 15 minutes. The test is considered positive if an inflammatory reaction appears in the oral cavity and other allergy symptoms.

Nasal

Conjunctival

Inhalation

Sublingual
And there is also an elimination method for identifying allergies. To do this, a person has to follow a strict diet for 5-10 days. If the patient's condition improves, then the reaction is positive. Contraindications for this case: diabetes mellitus, low body weight.

Immuno-laboratory research

This type of diagnosis has virtually no contraindications. Collecting biomaterial for analysis is a safe research method. It is even given to infants from 3 months and pregnant women.

Key Features:

Blood can be tested during an exacerbation of the disease , as well as throughout the entire course of treatment. 3-4 days before diagnosis, you need to exclude emotional and physical stress;
Tests are performed to determine the allergen and when skin testing is not possible;
The study reveals what a person is allergic to : food, animal dander, dust, fungi;
Tests are carried out in the morning on an empty stomach . First (7 days before) you need to stop taking antihistamines;
Blood is taken from a vein.

Laboratory blood diagnostics determines:

Number of total IgE antibodies;
The number of specific IgE and IgG antibodies.

Research stages:

First of all, the total level of immunoglobulin IgE is analyzed . In patients with allergies, it is increased and is more than 100 U/l in adults, and more than 20 U/l in children. The test confirms the presence of pathology, but does not provide specific data;
Then the “culprits” of the disease are determined, that is, specific IgE and IgG antibodies . They react with allergens. Thanks to this method, antibodies specific to a particular antigen can be detected.

Immunoblotting and allergen panels

Allergies can be successfully treated if the irritant is accurately identified. Thanks to immunoblotting, a special blood test is performed using electrophoresis.

The test results are compared with a pediatric panel. It is designed to control and identify dangerous allergens.

Stages of implementation:

If an allergy is suspected, the probable allergen is identified during the conversation;
Then the person's blood is drawn from a vein;
In the laboratory, the biomaterial is examined using electrophoresis and nitrocellulose paper.

When antibodies are detected, a dark stripe appears. Testing time is 7 days, in emergency cases – 2 days.

Advantages:

The analysis can be carried out at any age , starting from 6 months;
This method has no contraindications;
The study is carried out on an empty stomach ; before analysis, antiallergic drugs, fatty and fried foods, and alcohol are excluded;
The skin is not irritated and there is no contact with allergens;
Gives 100% accurate results.

During the study, 4 standard panels containing 20 allergens are used:

No. 1 (mixed) - pollen of alder, hazel, birch, plantain, wormwood, house dust mite, cat, dog, horse hair, milk, peanuts, flour, hazelnuts, egg white, etc.;
No. 2 (inhalation) - birch, alder, hazel pollen, house mite, cat and dog hair, fungi, etc.;
No. 3 (food) - peanuts, hazelnuts, almonds, eggs, potatoes, casein, flour, orange, tomato, etc.;
No. 4 (pediatric) - hair of dogs, cats, grass pollen, birch pollen, house dust mites, eggs, milk, casein, flour, potatoes and others.

The level of results obtained during testing in kU/L can be:

Short — 0,35-0,75;
Average — 0,75-3,55;
Explicit — 3,50-17,50;
High — 17,50-50;
Too tall — 50-100;
Extremely high - more than 100.

There is no direct relationship between the severity of symptoms and increased levels of specific IgE.

Types of tests for allergies

Allergy tests should be taken together. Often different tests can identify different precipitating factors.

First, the allergist will collect anamnesis, ask about what allergic reactions were observed, at what time, with what frequency, how long ago they arose, living conditions, heredity, etc.

After this, the doctor will prescribe a series of tests that will help identify allergens and prevent contact with them.

Allergy tests:

Skin tests. The most common and cheapest of all allergy tests. It is performed on the skin of the forearm or back. Different areas of the skin are marked and the allergen is applied to them either on a test strip or in the form of injections using micro-scratches. The test is painless, quick, but not always very informative; it is often supplemented with a blood test.
Blood test for eosinophils.
Eosinophils in the blood are indicators of an allergic reaction. A healthy person can have them in % of all blood cells, and he will not have any allergic reactions. If the figure ultimately exceeds 5%, it means that the body has a malfunction of the immune system, which provokes allergies. But it is impossible to say unequivocally that the increase in eosinophils in the blood was caused by an allergic reaction, so it is recommended to also take an immunoglobulin test.
Blood test for antibodies.
Antibodies, or immunoglobulins, in the blood demonstrate not only the presence of allergies, but also help to find the allergen. There is a panel of allergens, which includes a large number of likely provocateurs of an allergic reaction. This analysis is extremely informative, but quite expensive.
Provocative tests.
They are carried out only under the supervision of a doctor, traditionally in a hospital. The type of test depends on what specific allergic reaction the patient is concerned about. If there is rhinitis, then the allergen is injected directly into the sinuses, conjunctivitis - into the lacrimal gland. It is safe to carry out such tests only in the presence of a doctor, since even a small amount of the allergen can cause a strong reaction, swelling, which can only be stopped by medical staff. This diagnostic method is used in the latter case, when other tests have shown nothing.

Allergy test preparation and procedure

The doctor should tell you about the rules for preparing for the analysis, depending on the type of test.

The procedure and preparation for allergy tests depend on the type of test. If it's a blood test. Then the patient’s blood is taken from a vein during the day on an empty stomach. Blood is taken on an empty stomach so that it does not clot prematurely, so the nurse warns that it is necessary to visit the laboratory no earlier than hours after the last meal.

It is imperative to check with the doctor about the individual preparation.

There are a number of contraindications to similar procedures:

Exacerbation of allergies. Such tests are not carried out during an exacerbation of an allergic reaction, since the picture will be blurred by an already present allergy. Even with a seasonal exacerbation, you must wait until the allergy goes away. The exception is long-term allergies of unknown etiology.
Taking antihistamines. Antiallergy medications may make your body less sensitive to tests. Therefore, you need to stop taking antihistamines, wait a certain amount of time and then carry out tests.
Pregnancy.
No provocative or skin tests should be taken during pregnancy. Blood tests can also be unreliable, since during this period the body’s reaction worsens, and the allergy may go away after childbirth.

Skin tests and provocative tests are carried out under the supervision of a doctor. Conducting them at home without the help of others is dangerous. During skin tests on the hand in the forearm area, markings are made and different allergens are applied to different areas of the markings, which are certainly numbered.

Then they lightly scratch the skin and observe the reaction, which can appear within 10 minutes. In rare cases, you have to wait a day.

More information about allergy testing can be found in the video:

Skin testing can also be done in other ways. For example, an injection is used to inject the allergen under the skin. This method is considered the safest and most effective, since the allergen begins to act earlier, the reaction is most obvious.

Skin tests are also carried out using strips. Numbered strips with different allergens are attached to the skin and left for several days.

Such a reaction will not be rapid, since the allergens must penetrate the skin and enter the blood. These strips do not need to be wet or peeled off.

Features of taking an allergy test

To take the test, you need to go to a clinic with special conditions necessary for the test and an allergist. All manipulations are performed under the supervision of a specialist.

To obtain the most detailed information about the state of the body, doctors can prescribe a comprehensive examination, consisting of skin tests or immunological tests. Children are allowed to test 5 allergens in one procedure.

Allergen detection skin tests have one contraindication, which is the presence of a rash. In this case, doctors recommend a blood test.