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Allergy blood test: types of tests, preparation and interpretation of results
What is an allergy blood test and why is it needed?
An allergy is a reaction of the immune system to certain substances that are usually safe for most people. Symptoms can range from mild (runny nose, itching, rash) to severe (anaphylactic shock). To identify the cause of an allergic reaction, special laboratory blood tests are used to determine the level of immunoglobulins and specific allergens in the blood.
According to an allergist Oleksandra Hrytsenko,
“Allergy blood testing is an important diagnostic tool, especially for patients who cannot undergo skin testing. It allows the identification of potential allergy triggers without the risk of worsening symptoms.”
Allergy blood testing is a safe diagnostic method that can be performed regardless of the patient's age. It is especially useful for children, people with skin diseases, or those who have contraindications to skin allergy testing.
Types of blood tests for allergies
| Type of test | What determines | When used |
|---|---|---|
| Complete blood count (ZAK) | The level of eosinophils – cells responsible for allergic reactions | Primary analysis for suspected allergy |
| Level analysis total IgE | Immunoglobulin E concentration, which increases with allergies | Diagnosis of allergy susceptibility |
| Specific IgE to allergens | Determines the body's reaction to specific allergens (food, pollen, household) | Identification of a specific allergen |
| Immunoblotting | Comprehensive analysis that determines the reaction to allergen groups | Advanced diagnostics of allergic reactions |
Practical example
A 28-year-old patient consulted a doctor because of frequent runny nose and itching in the eyes, which worsened in the spring. An analysis was performed on specific IgE, who showed high sensitivity to pollen allergens (in particular, ragweed and birch). Thanks to the precise identification of the allergen, the doctor was able to select the appropriate therapy, which significantly improved the patient's quality of life during the flowering season.
How is a blood test for allergies performed?
The analysis involves taking venous blood in a laboratory setting. The basic principle of the test is to determine the level of antibodies IgE to certain allergens, which allows to identify the patient's individual sensitivity.
According to an immunologist Kateryna Litvinenko,
“Unlike skin tests, blood testing does not require direct contact with the allergen, making it safe for patients with severe allergies or at risk of anaphylaxis.”
The procedure takes a few minutes and does not require the body to come into contact with a potential allergen, making this method safe for people with severe allergic reactions.
What allergens can be detected with a blood test?
| Allergen group | Examples |
|---|---|
| Food allergens | Milk, eggs, nuts, fish, wheat, soy, honey |
| Pollen allergens | Birch, ragweed, wormwood, grasses |
| Household allergens | House dust, mites, mold |
| Animal allergens | Fur of cats, dogs, rodents, bird feathers |
| Drug allergens | Antibiotics, painkillers |
| Insect allergens | Venom of wasps, bees, ants |
How to prepare for an allergy blood test
To ensure that the test results are as accurate as possible, you must follow several rules:
- Donate blood on an empty stomach – do not eat for at least 8 hours before the procedure.
- Do not use antihistamines. before testing (in consultation with a doctor).
- Avoid stress and physical exertion the day before the analysis.
- Do not drink alcohol and coffee. 24 hours before the procedure.
- Do not smoke before the test., as this may affect immunoglobulin levels.
How to interpret the results
| IgE level (kIU/L) | Probability of allergy |
|---|---|
| Less than 0.35 | No allergies |
| 0,35-0,7 | Low probability |
| 0,7-3,5 | Moderate reaction |
| 3,5-17,5 | High response |
| 17,5-50 | Very high response |
| 50-100 | Severe allergy |
| More than 100 | Extremely high response |
According to the doctor of medical sciences Svitlana Koval,
“An elevated IgE level alone is not sufficient to diagnose an allergy. It is important to consider clinical symptoms and, in some cases, additionally perform skin prick tests or provocation tests.”
Benefits of allergy blood testing
- Safety – no contact with allergens during the test.
- Precision – the ability to determine the level of sensitivity to specific allergens.
- Applicability at any age – suitable for children and people at increased risk of anaphylactic reactions.
- Possibility of detecting hidden allergies – the analysis allows you to diagnose even latent forms of allergic reactions.
Blood allergy testing is one of the most informative diagnostic methods, allowing you to determine the causes of allergic reactions and choose the optimal treatment methods. Thanks to this test, you can identify allergens in a timely manner and avoid serious complications associated with the body's immune reactions.
