What are the blood tests for toxoplasmosis and what is the danger of the disease?

Blood test

Toxoplasmosis is a common disease caused by the penetration of parasites into the body. The disease provokes Toxoplasma gondii. The owner is a cat and other members of the family. Man and warm-blooded animals are a necessary intermediate "dwelling" of toxoplasm. Communication with domestic or wild animals, eating foods without proper thermal treatment, contact with soil during field or garden work, blood transfusions promote infection. The most dangerous when the parasite enters the body of a pregnant woman and the fetus is affected. The main method of diagnosing the disease is analysis for toxoplasmosis.


  • Why is a survey necessary?
  • Types of analyzes
  • Do you need preparation for analysis?
  • Decoding results by the presence of antibodies
  • What does avidity show?

Why is a survey necessary?

A large number of people are carriers of toxoplasma, and they do not notice any changes in their health. Under certain circumstances, the disease progresses, expressed in symptoms:

  • enlarged lymph nodes;
  • indigestion and intestines;
  • sensation of joint pain, general weakness;
  • increased sweating.

If an infection occurs, and the infected person is weakened by immune protection, toxoplasm enters blood and lymph, spread by internal organs, affects the nervous system, eyes, causing changes in the health.

Primary infection with toxoplasmosis during pregnancy, especially in the first half is very dangerous, entails a variety of vices in the development of the fetus, both physical and mental, can lead to intrauterine of death.

When the disease develops, the human body fights against it, actively develops antibodies to pathogens. The blood test for toxoplasmosis is performed in order to search for "agents" of immune defense, which are antibodies. To pass the analysis on toxoplasmosis is necessary in situations:

  • before the planned conception;
  • during pregnancy (at certain times);
  • with suspected fetal damage;
  • with an increase in the liver or spleen, lymph nodes, if there is no clear reason for the changes.
Bacteria Toxoplasma gondii

Types of analyzes

Blood for analysis for toxoplasmosis is tested in two ways. The first of these is the enzyme immunoassay (IF). When used in the test blood sample, specific components are isolated, the antibodies are proteins M (IgM) and G (IgG), they are synthesized when toxoplasma enters the blood.

The production of IgM proteins begins immediately after infection, lasts 20 days, corresponds to the acute form of the disease. IgG antibodies appear at the onset of the disease (on the third day), their number increases. Proteins of this group remain in the blood throughout the life of a person, protect the person from subsequent infections. Immunoenzyme method allows to determine one more indicator - avidity to toxoplasm or the ability of antibodies to bind to the toxoplasma shell, to violate it and destroy the parasitic organism.

Another type of study is the polymerase reaction method or PCR diagnostics. A highly informative way to confirm or disprove the results obtained by the first method. The presence or absence of toxoplasmosis indicates the presence of the DNA of the parasitic organism, on the molecules of which the sample is checked (urine, amniotic fluid, smear).


It is important that a reliable result can be obtained even in the first days of infection with the manifestation of primary symptoms.


Diagnostics using the PCR method is expensive, it is not carried out in all clinics due to lack of equipment. Qualitatively and quickly, the test can be checked in the Invitro network (on Michurinsky Prospekt) or in the Helix, Hemotest laboratory, whose branches are located in many cities.

Pathways of infection with toxoplasmosis

Do you need preparation for analysis?

Many patients are worried about the question when they receive a referral for analysis on toxoplasmosis - how to take it and whether it is necessary to prepare for the study. The test will show the results correctly if:

  • come to the laboratory on an empty stomach, on the eve it is forbidden to drink alcohol, fatty food;
  • To exclude the use of antiparasitic agents, antibiotics, drugs that help reduce the viscosity of the blood;
  • Do not use body care products with a pronounced aroma, perfume.

Use the venous blood for the dough, the fence is produced in the traditional way. Specialists can be warned about the residence of pets in the house.

Depending on the equipment and conditions of the clinical laboratory, the final result can be obtained within 1-3 days, it is written on the form, the result is transferred to the doctor, who must decipher the received values.

Blood donation for the study

Decoding results by the presence of antibodies

The interpretation of the analysis does not depend on who passed the test - adult or child, does not matter and sex. The main significance of the study is the determination of the phase of the disease in the presence of antibodies. Interpretation determines early (IgM) and late (IgG) antibodies, their combination, ability to avidity. The analysis of the toxoplasmosis assay is convenient using a table in which the information is presented graphically.

Blood test for pathogens

If two types of antibodies are not found in the blood sample - early and late, then the person does not have immunity to causative agent of toxoplasmosis, contact with it has not yet taken place, the disease does not develop, but infection can occur in any time. This situation requires special attention and control in the planning of conception, in the first trimester there is a possibility of primary infection of a woman, which has harmful consequences for the health of the baby.


Doctors recommend eliminating the factors that can lead to infection, follow the rules of hygiene.


Another combination of antibodies: IgM negative, IgG positive - penetration of a pathogenic microorganism happened a long time ago, immunity actively struggled with it, there is no danger to health, as well as indications to the appointment therapy. The presence of late antibodies indicates that there is sustained protection, no harmful effects occur, the person is in a recovery phase. It is necessary to study additionally the degree of stability of the produced antibodies, their avidity to toxoplasm.

An analysis of toxoplasmosis and subsequent interpretation of its results may show that the blood contains only early IgM antibodies. Such a figure in the meaning reflects a dangerous process - the infection occurred recently, an acute stage develops toxoplasmosis, immune protection is in the making, care is needed - drug treatment.


The situation when only IgM is produced is extremely dangerous for pregnant women - the fetus will be with anomalies.


Positive IgM and IgG means exacerbation of the disease. Such a process is the basis for the appointment of additional diagnostics and drug treatment. For women waiting for a child, the result with such a test value is undesirable because of the negative consequences for the fetus.

Some products that do not undergo the necessary heat treatment can cause contamination

What does avidity show?

As a result of the analysis, the degree of avidity to toxoplasma is indicated. A high indicator is the basis for assuming that immunity will provide stable protection, since antibodies have the maximum capacity to it. There are 3 degrees of the indicator, which is recorded as a percentage:

  • low - up to 40%, antibodies recently formed, immature, the indicator is determined at early stages of the disease;
  • average - 41-59%, does not indicate reliably at a certain stage of infection, the test must be repeated After a short time to refine the results, to track the full picture infection;
  • high - from 60%, in the human body "work" antibodies that can effectively hit a harmful microorganism that is the basis for withdrawal - the disease proceeds in a chronic form and the infection will not bring dangerous consequences, a peculiar norm.

Deciphering the analysis for toxoplasmosis is especially important in pregnancy. This test has the same value as the study for rubella antibodies, the detection of the cytomegalovirus titer. The study can be called a vital, especially necessary for the health of the unborn child.

Useful information can be found in the video lesson of the children's doctor Komarovsky who explains in detail how dangerous toxoplasmosis is, how long it takes for him to heal and how to protect himself from infection:

Another useful video will help to learn more about the dangerous disease and ways of protection:

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