How to understand whether a bacterial or viral infection is based on a general blood test

In the Lab4U online laboratory, we want each of you to be able to take care of your health. To do this, we tell you about health indicators in a simple and clear way!

As a rule, the most common question at the stage of diagnosing a disease that arises from a pediatrician or therapist is whether the patient has a bacterial or viral infection? It turns out that during viral and bacterial infections, two different processes occur in the body. Therefore, the strategy for further treatment depends on the answer to this question.

Lymphocytes - what are they, what are they?

Lymphocytes are one of the components of white blood cells; a complete blood test for lymphocytes . They play an important role in the formation of immune responses. Their function is to recognize pathogens and mutated own cells. After identifying a foreign object, lymphocytes destroy it in one way or another: phagocytosis, production of special antigens. To destroy their own cells that have degenerated into cancer or have undergone other changes, lymphocytes send a special chemical signal that causes such a cell to start the process of self-destruction. In addition to a general blood test for lymphocytes, a biochemical blood test is performed at the MedArt Medical Center.

There are three types of these cells:

1. T lymphocytes. They mature in the thymus. They play an important role in the fight against foreign bodies and infections. Some T-lymphocytes perform regulatory functions and are responsible for the duration and strength of the immune response. It is these cells that are affected when infected with HIV.
2. B lymphocytes. Their main task is to produce antibodies against viruses and other infectious agents. In addition, they are able to retain information about past diseases, thereby creating permanent immunity.
3. NK – cells. Their main function is to detect and eliminate body cells that have degenerated into malignant ones.

Lymphocytes are formed in the red bone marrow; their young, immature forms are called lymphoblasts. Maturation occurs in several stages, occurring not only in the bone marrow, but also in the lymphoid nodes and other organs of the lymphatic system.

The appearance of an increased number of lymphocytes can serve as a marker of bone marrow pathologies and the development of tumor processes in it. An increase in the level of lymphoblasts is also recorded during prolonged infectious processes. In this case, this serves as a sign of depletion of the body's defenses. The immune system does not have time to prepare a sufficient number of lymphocytes to fight the pathogen, and this becomes the reason for the appearance of a large number of lymphoblasts in the blood.

Additional examination of children

Listed above are just a few possible reasons why lymphocytes in the blood may be low. To clarify the diagnosis, a number of additional studies are required depending on the type of suspected pathology:

• for congenital diseases - detection of a genetic defect using molecular genetic methods;
• for autoimmune pathology - detection of autoantibodies;
• determination of the type of causative agent of an acute infectious process, for example, by bacteriological (culture of material) or serological method (pathogen antigens).

Indications for analysis

A general blood test for lymphocytes is prescribed if there is a suspicion of an increase or decrease in their number. The analysis can be prescribed for other reasons; it allows you to obtain a lot of valuable data about the state of the blood and the whole body. The main indications include:

• Detection of the immune response to the presence of pathogenic microorganisms.
• The state of human immunity.
• Physical and chemical composition of blood.
• Preventive analysis - to detect hidden changes in the blood formula that do not manifest themselves with specific symptoms.

How to pass the test correctly?

Proper preparation for analysis will ensure accurate research results. It is worth drawing the attention of parents to a number of basic rules.

1. It is best to donate blood on an empty stomach. This rule applies to older children. It is recommended not to feed infants for 2 hours.
2. It is advisable to reduce the amount of salted and smoked foods consumed.
3. It is advisable that the child does not run along the corridor of the clinic and does not cry in the treatment room. Since stress and physical activity can have an impact on the results of the study.
4. If your child is taking medications, it is important to check with your doctor to see if they will affect the test results. Don't do anything on your own!

Preparing for analysis

The analysis for lymphocytes is included in the general blood test, the rules for their conduct are the same. That is, such an examination does not require special preparation. There are only two conditions that must be met:

• Blood is taken in the morning.
• 8-12 hours before blood sampling you need to abstain from food.

You should also not smoke 2-3 hours before the procedure. Components of tobacco smoke can cause serious temporary changes in white blood cell levels. You should avoid drinking alcohol 2-3 days before taking the test, as alcohol can also affect the reliability of the results obtained.

If these requirements are not met, the accuracy of the examination may deteriorate, which will lead to the doctor receiving unreliable information and possible errors in diagnosis or re-prescribing the examination.

Research method

Material for analysis of lymphocytes is collected from a vein using a conventional syringe or a special vacuum system. The traditional technique of taking an analysis using a conventional syringe is currently outdated and can lead to the following difficulties:

• Blood clotting in a needle.
• Destruction of some blood cells.
• Long manipulation time.
• Contact of blood with the environment
• It is difficult to maintain the correct ratio of blood and reagents. In addition, the traditional technique does not exclude contact of medical personnel with the patient’s biomaterial, which can pose a health hazard. Therefore, many clinics use modern vacuum containers for blood collection.

Blood enters it due to the vacuum in the test tube; all parameters of the vacutainer are selected at the production stage in order to reduce the time for blood collection and ensure the correct ratio of the amount of reagent and blood.

Advantages of vacuum systems:

• A standardized blood collection process that takes minimal time.
• Contact of medical staff with the patient’s blood is completely excluded.
• Simple labeling and identification of samples, eliminating confusion with tubes.
• Almost painless procedure.

You can take blood for a general analysis from a finger, but at the moment this procedure is used much less frequently.

Norms

The normal level of lymphocytes in the blood depends on the age of the patient. In children, the number of lymphocytes is higher; over time, this figure gradually decreases. The number of these cells is influenced by the gender of the patient; in women the indicator is relatively higher. This is due to the greater activity and adaptive capacity of the lymphatic system of the female body.

For what symptoms is it necessary to determine lymphocytes in the blood?

Reduced lymphocytes in the blood are called lymphopenia.

The following symptoms will indicate that lymphocytes are low:

• the occurrence of infectious diseases , or rather their reappearance, for example, frequent pneumonia;
• the presence of skin lesions , leading, for example, to dermatitis.

Usually, when lymphocytes are low in a child, it is difficult to suspect only from clinical manifestations.

The level of lymphocytes decreases during infectious processes, but after recovery everything returns to normal.

Lymphocytes are increased

The reason why lymphocytes are elevated is often a variety of viral infections. This increase is called lymphocytosis, and is most often recorded in diseases caused by viruses:

• Epstein-Barr.
• Adenovirus.
• Herpes.
• Childhood infections (rubella, measles, mumps).

The number of lymphocytes may increase with some bacterial infections, such as syphilis, whooping cough, or tuberculosis. Diseases caused by protozoa, such as malaria and toxoplasmosis, can lead to lymphocytosis. Often, an increase in lymphocytes is caused by helminthic infestations.

Lymphocytes may be elevated for reasons unrelated to infection. These include:

1. Hypersensitivity reactions.
2. Stress lymphocytosis.
3. Autoimmune diseases.
4. Disorders of the endocrine organs, especially the thyroid gland.
5. Development of tumors and pretumor processes.

The most striking signs of an increase in the number of lymphocytes include:

• Enlarged liver, spleen and lymph nodes.
• General malaise, manifestations of respiratory infections, redness and swelling of the mucous membranes.
• A sharp increase or decrease in temperature, accompanied by chills.
• Dyspeptic symptoms - vomiting, stool disorders, nausea.
• Nervous system disorders due to elevated temperature.

It should be borne in mind that lymphocytosis does not always manifest itself through severe symptoms. Often, elevated levels of these cells are discovered by chance. Only a doctor can accurately determine the reason why a change in the blood formula occurred; this often requires additional tests.

To eliminate lymphocytosis, you need to cure the disease that led to an increased immune response. It is important to understand that the hematopoietic system responds to recovery with a certain delay. Even after complete recovery, lymphocytosis can persist for up to several months.

Lymphocytes are low

A decrease in lymphocytes is called lymphopenia. This condition is typical for the following diseases:

• AIDS.
• Long-term, severe infections.
• Bone marrow pathologies.
• Tumors of lymphatic tissues.
• Exposure to radiation.
• Taking certain groups of drugs, such as cytostatics.
• Pregnancy.

In most cases, a decrease in the level of lymphocytes indicates a depleted immune system, when the body, for various reasons, is unable to maintain the required level of these cells in the blood.

Lymphopenia rarely presents with characteristic symptoms. The most common signs of this condition include:

• Reduction or complete absence of tonsils and other peripheral lymph nodes.
• Skin diseases - eczema, pyoderma.
• Common signs of blood diseases are ulcers of the oral mucosa, petechiae, pallor, and jaundice.
• Enlarged liver and spleen.

As in the case of lymphocytosis, to normalize the level of these cells, it is necessary to eliminate the cause that led to the pathological condition. You need to see a doctor who can establish an accurate diagnosis and prescribe the correct treatment regimen.

In the case of lymphopenia in pregnant women, with a moderate decrease in the level of lymphocytes, there is no need to take special measures. Enhanced monitoring of your health status and regular completion of all necessary examinations is sufficient. If there is a sharp drop in lymphocytes, you should seek medical help for additional diagnostics.

Conclusions:

To summarize all of the above, a blood test with microscopy can determine what kind of infection (viral or bacterial) we are talking about, how the body reacts to it, and whether it needs the active help of antibiotics. Without the test results during examination, the doctor will not be able to immediately determine the type of infection and prescribe adequate treatment.

If necessary, take a general blood test with microscopy and bring the results to your doctor. This way he can prescribe the right treatment for you.

You can take a general blood test with microscopy with a 50% discount. The analysis will be ready within 1 day. You will receive the results by email as soon as they are ready.