Bronchial asthma is a chronic respiratory disease. Due to the constant inflammation of the bronchi, the patient’s respiratory function is impaired, which can be life-threatening.

But before prescribing treatment, it is important to accurately diagnose, since there are also other pathologies with similar symptoms, the treatment methods for which are very different. It is for this that the patient is invited to pass one or another test for asthma.

After passing the prescribed examination, the patient is given an accurate diagnosis and the correct treatment is prescribed.

Diagnostics of the bronchial asthma

First of all, the doctor examines the patient, listens to his complaints and records the observed signs of pathology. At different stages of the development of the disease, the symptoms may be different.

So, for example, at the initial stage, the patient may only be bothered by a cough. Examination of the patient during an attack will be much more informative, but asthma, like any other disease, is better and easier to treat until complications develop.

After the examination, the doctor prescribes additional examinations to clarify the preliminary diagnosis of bronchial asthma. To do this, the doctor gives the patient a referral to the laboratory, specifying what tests are required.

Blood tests are required for a preliminary diagnosis.

If, according to the results of laboratory tests, the suspicion of bronchial asthma is confirmed, the patient is sent for a respiratory function test. It is after these procedures that the final diagnosis is made.

Laboratory tests in the diagnosis of asthma

After the examination, the doctor without fail sends the patient to take the tests necessary to clarify the diagnosis of bronchial asthma. There is a whole body of research to be done.

After studying the obtained biomaterial samples, it is possible not only to make a preliminary diagnosis, but also to identify other abnormalities. Standard examinations include:

General blood analysis. Its main purpose is to determine the level of hemoglobin, counting leukocytes and erythrocytes, as well as measuring the erythrocyte sedimentation rate (ESR).

  • Sputum analysis.
  • Coagulogram.
  • Blood chemistry.
  • Immunological blood test.
  • Analysis of bronchoalveolar lavage.

If these tests are insufficient, your doctor may order potential asthmatics to take additional blood tests or other tests to confirm or rule out asthma.

Blood tests for bronchial asthma

A blood test for suspected bronchial asthma is mandatory. Analyzing the results of these studies, the specialist makes a conclusion about the nature of the disease.

So, if bronchial asthma is mild, and the attacks are rare and quickly pass, the indicators of a general blood test remain unchanged.

If there is a tendency to an increase in the content of erythrocytes and the level of hemoglobin, there is a risk of a rapid deterioration in the patient’s condition.

That is why the patient needs to pass a whole complex of necessary tests if bronchial asthma is suspected, and repeatedly undergo these studies in the future.

Laboratory monitoring of the course of the disease makes it possible to respond in a timely manner to any changes associated with both the pathology itself and with concomitant diseases.

General blood analysis

A general blood test is the simplest and most common blood test; it is also prescribed for bronchial asthma. Blood sampling is done both from a vein and from a finger.

Preparation for the study is standard. No additional effort on the part of the patient is required.

The main determined indicators:

  • ESR;
  • hemoglobin level;
  • the number of red blood cells.

If the disease is in remission or proceeds in an intermittent form, all these indicators will remain within normal limits.

If the inflammatory process progresses, the ESR rate will increase. With significant oxygen starvation, a decrease in hemoglobin level will be observed. Development of anemia is possible.

Biochemical analysis

A biochemical blood test is considered more accurate than a general one. Even minor changes in the condition in the event of bronchial asthma will cause changes in blood counts.

This analysis allows not only to clarify the diagnosis, but also to determine the severity of the course of the disease.

Blood for research is taken only from a vein.

With bronchial asthma, a significant increase in the content of alpha-2 and gamma globulins, fibrin, sialic acids is observed in the blood. If the pathology is caused by the development of an infection in the body, then haptoglobulin will be increased.

Immunological blood test

This examination is prescribed if it is necessary to find out whether asthma is allergic or infectious. Diagnostics of the atopic form of pathology consists in the detection of immunoglobulin E and antibodies.

Immunoglobulin E is a protein that belongs to class E antibodies. It is he who is responsible for the allergic reaction in the body. When a protein comes into contact with an allergen, a response is formed in the form of a release of histamine, serotonin and other compounds that cause an attack.

The analysis is taken from a vein in compliance with all standard requirements for blood sampling.

Arterial blood gas analysis

Revealing changes in blood gas composition is an important study prescribed for asthma. With its help, the severity of the disease is determined.

This study is prescribed if the patient has the following manifestations of the disease:

  • severe shortness of breath;
  • significant increase in heart rate;
  • change in the shape of the chest;
  • loss of consciousness.

If the amount of oxygen in the analyzed blood sample is greatly reduced, and the content of carbon dioxide, on the contrary, exceeds the norm, the patient is sent for oxygen inhalation. In asthma, such indicators indicate oxygen starvation.

Preparation for research

Conducting blood tests for bronchial asthma is very important to clarify the diagnosis and determine the severity of the disease.

Based on these data, treatment is prescribed or the patient is sent for additional examinations.

However, for the results to be reliable, the patient requires a simple, but very important preparation.

Before the procedure, you must follow the following guidelines:

  1. A blood test (as in any other case, not just for asthma) is taken on an empty stomach. A snack is allowed no earlier than 7 hours before the delivery of the biomaterial.
  2. After taking the medication, at least 12 hours should pass.
  3. Before donating blood, you should exclude the use of alcohol, fatty and fried foods.
  4. Intense physical activity should be avoided.

Blood test results and their implications for diagnosis

If a patient is first diagnosed with bronchial asthma, the results of blood tests will not only confirm the diagnosis, but also determine the severity of the disease. When studying the results, the doctor pays attention to the following parameters:

  1. ESR. The erythrocyte sedimentation rate is an important indicator. In bronchial asthma, its values ​​remain within the normal range. But if an infection enters the body, the ESR rises sharply.
  2. Eosinophils. Their level is the main diagnostic criterion. In asthma (in the acute stage), their content is higher than normal. However, in the stage of remission, this figure returns to normal.
  3. Neutrophils. If the number increases, the doctor may suggest the development of asthma.
  4. Hemoglobin. With asthma, its amount increases.

When making a diagnosis, the doctor takes into account not only these basic blood parameters, but also the clinical signs of asthma, as well as the results of other examinations.

The diagnostic method alone cannot confirm that the patient has this particular disease.


Blood tests for asthma are of great diagnostic value. On their basis, the doctor can both assume the presence of the pathology itself, and determine the degree of its severity.

However, a diagnosis cannot be made based on blood tests alone. For this, a number of diagnostic examinations are required to either refute or confirm the presence of the disease.

To get the most accurate result, the patient must take a responsible approach to this procedure and properly prepare for it. Only in this case, the doctor will be able, based on the data obtained, to prescribe the most effective treatment.