How Is The Analysis For Toxoplasmosis Done During Pregnancy: Methods, Norms, Decoding

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How Is The Analysis For Toxoplasmosis Done During Pregnancy: Methods, Norms, Decoding
How Is The Analysis For Toxoplasmosis Done During Pregnancy: Methods, Norms, Decoding

Video: How Is The Analysis For Toxoplasmosis Done During Pregnancy: Methods, Norms, Decoding

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Video: Food Safety Moms-to-Be -- Toxoplasma 2023, February
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How to do an analysis for toxoplasmosis during pregnancy: methods, norms, decoding

Toxoplasma is a parasite that lives and reproduces in the body of cats, but it can choose almost any living creature as an intermediate host, and often a person becomes it. Infection with toxoplasmosis is not dangerous, often the disease is asymptomatic. The time to worry about this comes when you have to be tested for toxoplasmosis during pregnancy. For expectant mothers, the issue of immunity to toxoplasmosis is extremely important, since it directly affects the health of the unborn child.

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For expectant mothers, the issue of immunity to toxoplasmosis is extremely important, since it directly affects the health of the unborn child.

Why is toxoplasmosis dangerous during pregnancy

Once having been ill with toxoplasmosis, a person acquires immunity to the disease. Symptoms of the acute course of the pathology are often similar to a mild cold, therefore, in most cases, toxoplasmosis goes unnoticed, and the immune defense remains.

The main danger of toxoplasmosis that must be taken into account when planning pregnancy is the risk of primary infection while carrying a child. Depending on at what stage of pregnancy the infection occurs, the likelihood of consequences for the development of the fetus is different.

How the infection affects the fetus

A woman can become infected with toxoplasma not only through direct contact with a cat: the pathogen can live in the ground, sand, raw or poorly processed meat.

In the first trimester, the probability of infection is small, but the consequences of the disease can be extremely severe: congenital toxoplasmosis, miscarriage, intrauterine death. In the second trimester, infection threatens pathologies of the central nervous system and organs of vision. In the future, this may result in epilepsy, mental retardation, blindness, etc. In the later stages of pregnancy, the risk of fetal infection increases to 60%, the symptoms in this case may be subtle, but the likelihood of latent toxoplasmosis remains, which can appear many years later.

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A woman can become infected with Toxoplasma through direct contact with a cat.

Diagnostic methods

The presence of immunity against toxoplasmosis is detected with the help of tests that every woman has to take when registering for pregnancy.

Among other examinations, a woman must take a blood test for TORCH infection (TORCH) - toxoplasmosis, rubella, cytomegalovirus infection, herpes.

They are united by a common symptom: in case of primary infection during pregnancy, the consequences for the development of the fetus can be so severe that in some cases, with a positive result, it is recommended to terminate the pregnancy for medical reasons.

When examining blood for the presence of antibodies to Toxoplasma, not only the fact of infection is determined, but also its "prescription".

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If the result is positive for toxoplasmosis, termination of pregnancy for medical reasons is recommended.

Whether a woman became infected during pregnancy or experienced toxoplasmosis several months or years ago, the difference in results will be important. The analysis consists in identifying class M and G immunoglobulins, i.e. antibodies to infection. In the diagnosis of toxoplasmosis, several research methods are used.

RNIF

The RNIF method - the reaction of indirect immunofluorescence - is considered the most reliable and sensitive among similar methods. A special "labeled" serum is applied to the obtained preparation of the serum of the test blood, after which a bunch of antigen and antibody is formed in the preparation.

RSK

The immunological method of toxoplasmosis analysis, which is called the complement fixation reaction, is based on the ability of the antigen-antibody complex to bind to complement - proteins responsible for immune responses. The complexes capable of binding are calculated according to the following scheme:

  • detection of antigens or antibodies in the serum of the analyzed blood using serum;
  • addition of complement and hemolytic system.

With the correct presumptive determination of antibodies at the first stage, the complement binds to the antigen-antibody complex, and the result will be positive. If antigens and antibodies do not match, binding will not occur - the result is negative.

The enzyme immunoassay has a number of advantages (cost, sensitivity, small volume of the studied drug, the possibility of automation and instrumental recording of the reaction), therefore, in some conditions, this method is preferred
The enzyme immunoassay has a number of advantages (cost, sensitivity, small volume of the studied drug, the possibility of automation and instrumental recording of the reaction), therefore, in some conditions, this method is preferred

The enzyme-linked immunosorbent assay has a number of advantages (cost, sensitivity, small volume of the studied drug, the possibility of automation and instrumental recording of the reaction), therefore, in some conditions, this method is preferred.

Immunological method for the analysis of toxoplasmosis of the blood under study using serum
Immunological method for the analysis of toxoplasmosis of the blood under study using serum

Immunological method of analysis for toxoplasmosis of the blood under study using serum.

When examining blood for the presence of antibodies to toxoplasma, not only the fact of infection is determined, but also its "prescription"
When examining blood for the presence of antibodies to toxoplasma, not only the fact of infection is determined, but also its "prescription"

When examining blood for the presence of antibodies to Toxoplasma, not only the fact of infection is determined, but also its "prescription".

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ELISA

The enzyme-linked immunosorbent assay has a number of advantages (cost, sensitivity, small volume of the studied drug, the possibility of automation and instrumental recording of the reaction), therefore, in some conditions, this method is preferred. It is used to diagnose many infections of various etiologies, including toxoplasmosis. It is carried out in two stages:

  • interaction of antigen and antibody;
  • visual or spectrophotometric registration of the mixture staining reaction (enzymatic indication of the "antigen - antibody" link).

Decoding the results

The results of a blood test for immunoglobulins M and G to Toxoplasma determine both the fact of infection and the presence or absence of immunity to this infection.

If antibodies of class M are found in the blood at the time of analysis in the absence of IgG, this indicates a recent infection, i.e. acute form of toxoplasmosis. This is the least favorable option when it comes to pregnancy. IgM can sometimes give a false positive result due to the high sensitivity of some tests. In this case, the analysis is repeated after 2-3 weeks.

If, as a result of the analysis, both types of immunoglobulins are determined, the infection occurred within a year before the analysis: the appearance of IgG means the formation of immunity against Toxoplasma. For a more accurate result, it is recommended to donate blood again after 2-3 weeks. An increase in IgM levels indicates the early stages of infection, and a decrease in the formation of immunity. Over time, immunoglobulin M is cleared from the blood, and IgG acquires a high avidity - the ability to bind antigens.

When, as a result of the analysis, only IgG positive is detected, this means the formed immunity against toxoplasmosis, i.e. a person became infected and recovered more than a year ago, re-infection does not threaten him.

What indicators are the norm

There is no clear norm for antibodies to toxoplasmosis, since the pathogen should not enter the human blood. Nevertheless, there are reference indicators on the basis of which the result of the analysis is considered positive or negative. For IgG, a level of less than 9.0 g / l is considered negative, more than 12 - positive. For IgM: less than 0.8 g / l - negative result, more than 1.1 - positive.

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