Blood test for toxoplasmosis: how to take it, explanation

Imagine that you are expecting a child and want to be able to decipher the test for toxoplasmosis during pregnancy, find out what antibodies to the pathogen are and what the ratio of immunoglobulins M and G (IgM, IgG) shows - these and other questions are covered in the article.

How to identify toxoplasmosis in pregnant women? Take a blood test from a vein to check for the presence of antibodies in the body of the expectant mother.

Often young women are interested in when it is necessary to get tested for toxoplasmosis: before pregnancy, when planning pregnancy, or after conception. It is best to get tested as soon as there is a possibility of fertilization . Why? Because if Toxoplasma is detected in pregnant women and they lack immunity to it, most doctors advise terminating the pregnancy, and you can become pregnant again only six months after treatment.

Toxoplasmosis is a parasitic infection with a wide range of clinical manifestations and course of the process: from healthy, asymptomatic carriage to severe, lethal forms of the disease. Since 1972, WHO experts have classified toxoinfestation as a zoonotic disease, the most dangerous to our health.

What are the symptoms of toxoplasmosis during pregnancy, why is it dangerous and what consequences can it have for the unborn child is described in more detail in a separate article - follow the link. There is also prevention of toxoplasmosis in pregnant women. Below we will dwell on the analysis for toxoplasmosis in pregnant women.

What is toxoplasmosis?

The infectious disease toxoplasmosis is caused by parasites. The main carriers of pathogens are cats. But animal waste products end up in the soil, from where they can spread to temporary carriers: rodents, goats, cows. Pathogen spores can get onto vegetables with the soil. Thus, a person can become infected through unwashed hands, especially after contact with animals, as well as by eating insufficiently processed meat and vegetables. When the parasite enters the body, toxoplasmosis develops. The antibody level in this case assumes the presence of IgM immunoglobulin as a result of the analysis.

The body's response to toxoplasmosis infection

Like any other infection, the human body reacts to infection with toxoplasmosis by activating the immune defenses. Namely, the production of special antibodies, immunoglobulins of the IgG and IgM protein groups.

Having detected a pathogenic microorganism (antigen), cells of the immune system begin to produce antibodies that are aimed at eliminating a specific infection. These helpers in the fight against disease are called “IgG immunoglobulins.” Finding a specific antigen, they bind to it, destroying the structure. With the development of a disease such as toxoplasmosis, the norm in the blood of IgG is the detection of this group of immunoglobulins on the third day after infection. They persist throughout life, protecting a person from secondary infection. Thus, you can become infected with toxoplasmosis only once, after which a strong immunity to the parasite that causes the disease is developed.

When infected with toxoplasmosis, other groups of immunoglobulins, namely IgM, come to the aid of the body in the fight against the disease. Toxoplasmosis detected? The norm of antibodies in this case is the detection of immunoglobulins of the IgM group in the blood immediately after the parasite enters the body. But IgM immunoglobulins cannot protect a person from re-infection, since they stop being produced approximately 2-4 weeks after infection.

Properties of IgG immunoglobulins

It is worth considering in more detail the functions and properties performed by IgG group immunoglobulins in the body when infected with a disease such as toxoplasmosis. The IgG norm is an ambiguous concept. The presence of immunoglobulins of this group may indicate both the acute phase of the disease and a long-term process. How do antibodies fight disease? They perform a number of functions that protect the body and adversely affect the viability of the pathogen, namely:

• neutralize toxins produced by the parasite;
• participate in the process of avidity (bind with the pathogen);
• stimulate phagocytosis;
• have the ability to penetrate the placenta, thereby forming passive immunity in the fetus.

An interesting and important fact is that it is the immunoglobulin of the IgG group that makes up 80% of all immunoglobulins in the body. In addition, in chronic forms of infections and autoimmune diseases, the percentage of IgG immunoglobulins increases.

Interpretation of immunoglobulin IgG indicators

A quantitative measurement of immunoglobulins is not routinely done when testing for toxoplasmosis. The normal level in the blood is an indicator of the detection or absence of immunoglobulins. Most often, the results of the analysis indicate such designations as “positive” or “negative”. But in some cases, according to indications, the doctor may prescribe a special quantitative analysis. It is quite difficult to give specific standards for IgG immunoglobulin indicators, since each laboratory has its own criteria. Such differences are due to the use of different chemical reagents during the test for toxoplasmosis in the blood. The norm varies markedly depending on the laboratory. As an example, the following norms of indicators can be given:

1. How to interpret test results for toxoplasmosis? The normal IgG level is below 700 mg/dl. A positive test result for measuring the amount of IgG immunoglobulins is 700–1600 mg/dL or 7–16 g/L. Indicators below the specified limits are considered a negative result.
2. Using other units of measurement, the following norms for IgG immunoglobulin indicators are indicated: above 12 U/ml is considered a positive result, below 9 U/ml is considered a negative result, indicators between the indicated norms are questionable and require additional research.

Regardless of how the toxoplasmosis test indicators are designated, deciphering the result has the same meaning. Tested positive for toxoplasmosis in your blood? The norm is the presence of IgG antibodies and the absence of IgM. The presence of IgG immunoglobulins in the test material indicates that the body has encountered the causative agent of toxoplasmosis. This means that a person is reliably protected from secondary infection. But at the same time, such results may indicate a recent primary infection. To confirm or refute this assumption, it is necessary to analyze the indicators of IgM immunoglobulins, which appear in the body only during the acute phase of the disease. Accordingly, the presence of such antibodies indicates primary infection and a serious danger to the fetus. In such a situation, the doctor diagnoses “toxoplasmosis”. The normal level in the blood is the absence of IgM antibodies. Such indicators indicate a long-standing infection and the absence of any danger to the body.

If the test results indicate the absence of IgG immunoglobulins in the body, special measures should be taken to prevent infection during pregnancy, since such results indicate the absence of protective antibodies against toxoplasmosis.

IgG avidity to Toxoplasma

Methods for diagnosing toxoplasmosis

There are the following types of diagnosis of toxoplasmosis:

1. Immunological and serological. They are based precisely on the body’s ability to produce antibodies to infection. Using special test systems, the presence or absence of IgG and IgM immunoglobulins is determined. In this way, it is possible not only to detect the presence of protective antibodies in the body, but also to promptly diagnose the acute phase of toxoplasmosis. Have you ordered a blood test for toxoplasmosis? The norm is the detection of IgG antibodies and the absence of IgM.
2. Methods for direct detection of the parasite are studies using microscopy or PCR diagnostics.
3. Instrumental methods are used only in complicated and controversial cases. Ultrasound, computer examination and others are used.
4. A biological test can also indicate the presence of IgG immunoglobulins in the body. After subcutaneous administration of a special allergenic drug, the reaction is observed for two days. When swelling appears, a positive result is recorded.

What to do if tests show deviations from the norm?

Regular screening for toxoplasmosis is a guarantee of an easy pregnancy. Doctors recommend repeating the test every three months. If a general blood test for toxoplasmosis raises suspicion among doctors, a repeat test is prescribed. When there are no changes in the studied material, the pregnant girl is offered a course of treatment. When antibodies are detected, the doctor can only regularly monitor the general well-being of the patient; if there is no immunity, then in severe cases the solution to the problem lies in emergency termination of pregnancy.

Method for diagnosing toxoplasmosis ELISA

Most often, enzyme immunoassay is used to determine toxoplasmosis. It is this method that allows you to determine the duration of infection and establish the acute phase of the disease. Such indicators can be identified through the detection of IgM immunoglobulins. If the form states: “toxoplasmosis: normal in the blood,” the result means that there is no acute phase of the disease.

The decoding is standard and has no special features when conducting analysis during pregnancy.
Let’s take a closer look at what the results mean: “acute phase of the disease” and “toxoplasmosis: normal in the blood.” The table below clearly demonstrates the indicators and their designation. Namely: Indicators of analysis for toxoplasmosis using the ELISA method

Forms and symptoms

There are 2 types of disease: acquired and congenital.

The first, in turn, can be:

1. Spicy. It is characterized by many pronounced symptoms: deterioration in general health, pain in muscles and joints, elevated body temperature, enlarged lymph nodes, and a rash all over the body (except for the feet, palms and head). In addition, signs of pneumonia, hepatitis, and damage to the nervous and cardiovascular systems appear.
2. Chronic. Its peculiarity is a long course, periods of exacerbation pass into the stage of remission and vice versa. The main symptoms of toxoplasmosis in humans in this form are: muscle and joint pain, memory loss, irritability, enlarged lymph nodes, constipation, intestinal colic; palpation reveals lumps in the muscles, eye damage, and disturbances in the functioning of the cardiovascular system.
3. Latent. This form is the most common and occurs, as a rule, without any signs indicating an existing disease. It is diagnosed only after a person has been tested for toxoplasmosis. A severe course occurs in people with HIV. Almost all organs are affected, which can lead to death.

Congenital toxoplasmosis is a form of the disease in which a child is infected in utero from the mother. If the infection occurs in the first half of pregnancy, the fetus dies in most cases; in the second half, the baby is born with serious brain pathologies. In this case, the child experiences: convulsions, epilepsy, tremor, nystagmus, increased head size, tense fontanelles, thinned skull bones, optic nerve atrophy, mental retardation, psychoemotional disorders, jaundice. The addition of a secondary infection provokes an increase in the degree of brain damage, which can lead to death.

Thus, symptoms of toxoplasmosis in humans can be either absent or pronounced. Several years ago, children with the congenital form died, as a rule, in the first years of life. At present, timely testing for toxoplasmosis plays a decisive role - if an infection is detected, it is possible to stabilize it or get rid of it altogether (but some residual effects may be observed).

Toxoplasmosis: normal in the blood during pregnancy

A seemingly harmless disease such as toxoplasmosis can cause serious complications in people with weakened immune systems. But the disease poses a particular danger to a pregnant woman and her fetus, since the parasite can penetrate the placenta and infect the unborn baby. The baby’s immature immunity is not able to resist the pathogen, and in many cases the child dies. It is worth noting that when a pregnant woman is infected in the early stages, there is a high probability of miscarriage, fetal death, and the formation of pathologies incompatible with life.

Infection in the later stages leads to premature birth, stillbirth, and the appearance of a child with serious developmental pathologies, such as:

• inflammation of the retina, blindness;
• deafness;
• enlarged spleen and liver;
• disruption of the development of internal organs;
• jaundice;
• damage to the central nervous system (convulsions, paralysis, hydrocephalus, mental retardation, epilepsy, encephalitis);
• pneumonia;
• disruption of the heart;
• external deformities: cleft lips and palate, pathologies of limb development, hernias, hermaphroditism, strabismus, cataracts and more.

Many of the above congenital pathologies lead to infant mortality within the first few weeks of life or to severe disability. There are cases of the birth of a child without obvious, at first glance, pathologies. But during the first year of life, symptoms of acute toxoplasmosis appear.

Considering the high level of danger of infection for an unborn baby, doctors during the period of planning, conception, and throughout pregnancy prescribe women a comprehensive test for TORCH infections, which includes testing for toxoplasmosis. The norm of tests during pregnancy is no different from generally accepted indicators.

Timely treatment significantly increases the chances of having a healthy baby. In this case, the benefits of the drugs used exceed the possible harm they cause.

Why are Toxoplasma dangerous for humans?

Clinically, toxoplasmosis manifests itself extremely rarely, only in 1-5% of all infected cases. As a rule, its pronounced course can be observed in persons with immunodeficiency (AIDS-associated infection), which will be expressed by the development of lymphadenopathy, myocarditis, encephalitis and other changes. It would seem that it does not manifest itself in any way, does not require treatment, so there is no need to worry. However, it is not.

Toxoplasmosis really has little effect on humans, but it poses a serious threat to the fetus, the normal intrauterine development of which toxoplasma will disrupt. Therefore, for a woman planning to become a mother, toxoplasmosis will not become a “time bomb”, since, having penetrated the placenta, it will cause irreparable harm to her child. The parasite can kill the fetus or cause numerous deformities.

Indications for treatment of toxoplasmosis

The analysis form indicates the result “toxoplasmosis: normal in the blood” - in this case, treatment is not required. In most cases, the human immune system can cope with a pathogenic microorganism on its own. Treatment is prescribed only for various immune disorders in the following cases:

• in acute toxoplasmosis to prevent serious complications in AIDS patients and pregnant women;
• in the chronic form of the disease during the period of exacerbation in order to form a normal immune response;
• treatment can be prescribed for chronic toxoplasmosis in the event of the development of chorioretinitis, infertility, or miscarriage.

Treatment of toxoplasmosis in people with weakened immune systems in the absence of pregnancy

People with weakened immune systems may be prescribed different medications, depending on symptoms and medical history:

• "Fansidar."
• "Delagil."
• "Tetracycline".
• "Doxycycline."
• "Prednisolone."
• "Spiramycin."
• "Trichopolus".
• Calcium folinate.

Pregnant women should not use the above drugs.

Treatment of toxoplasmosis in pregnant women

How to decipher a test for toxoplasmosis in an expectant mother? The norm during pregnancy is also determined by: the presence or absence of the causative parasite or protective antibodies of the Igg and IgM groups.

If the analysis confirms the presence of an acute phase of infection, one of two types of therapy can be used:

1. Rovamycin can be prescribed in various courses: 1.5 million units twice a day for 6 weeks; 3 million units twice a day for 4 weeks or 3 million units three times a day for 10 days. This treatment is prescribed no earlier than 16 weeks of pregnancy.
2. A complex consisting of Pyrimethamine and Sulfodaxine. The dosage and duration of the course are indicated by the doctor. Treatment can be prescribed after 20 weeks of pregnancy.
3. For eye inflammation, treatment with Prednisolone is necessary.
4. Spiramycin is also used in uncomplicated cases.

Rules for taking the analysis

How is a blood test done for toxoplasmosis? The material is collected in a sterile clinic environment. No special preparation is required for donating blood, there are only general recommendations:

1. Blood is donated in the morning on an empty stomach, you can drink a glass of water.
2. A couple of days before the test, you need to give up fatty, spicy foods, and alcohol.
3. You must not smoke on the day of sample delivery.
4. You should stop taking medications 1-2 weeks before the test.

If the medication cannot be stopped, then the names and doses of the drugs should be reported to the laboratory assistant and the attending physician.

The amount of blood sufficient for the study is 3-5 ml.

Prevention methods

If you are planning a baby, and test results show the absence of antibodies to toxoplasmosis, there is no other way to protect your unborn baby from the disease other than preventive measures. Based on knowledge about methods of infection, the following preventive measures can be outlined:

• minimize contact with animals throughout the entire period of pregnancy;
• do not eat raw or undercooked meat, unwashed vegetables;
• work with soil only with rubber gloves;
• Remember to wash your hands thoroughly and often.

Such simple rules will help preserve not only the health, but also the life of the unborn baby and the expectant mother.

Based on the information presented in the article, we can conclude that toxoplasmosis is an extremely dangerous disease for the expectant mother and her baby. But modern medicine is able to timely detect specific antibodies that protect the body from infection. In this case, it is necessary not only to submit it on time, but also to correctly interpret the results of the test for toxoplasmosis. The norm for pregnant women is no different from generally established indicators. Thus, the presence or absence of IgG immunoglobulins may indicate directly opposite clinical pictures. Therefore, trust a specialist - strictly follow all his recommendations, do not decipher the results yourself. In this case, the probability of a successful birth of a healthy child is very high. Be healthy!

Interpretation of results

The immune response to Toxoplasma infection is highly variable, and deciphering the results of serological tests is sometimes not so simple. But so far this is one of the most advanced methods for determining infection. The interpretation is considered separately for different antibodies; the norm may sometimes change depending on the situation that arises.

What does the antibody test indicate? The picture is like this:

Deciphering the analysis for toxoplasmosis is possible only with an indication of avidity:

• low (less than 40), manifested during primary acute infection;
• medium (up to 59), considered doubtful and requiring re-analysis;
• high (more than 50), considered normal, immunocompetent, not allowing an acute course of the disease.

When tested for toxoplasmosis, the detection of IgM in pregnant women does not clearly indicate the presence of an acute (primary) infection and always requires additional laboratory tests. In some cases, the acute phase of toxoplasmosis may occur without the presence of IgM or have low antibody titers.

The search for IgA and IgE antibodies can complement the diagnosis of toxoplasmosis. IgA antibodies appear later than IgM antibodies, but they can, like IgE, indicate an acute infection. At the same time, the period of positive serological reactions to IgA can take 12 months. Therefore, one-time confirmation of the presence of these antibodies without an IgG avidity rating cannot be the basis for diagnosing an active infection.

The test results are always interpreted by a doctor. This is his area of ​​responsibility, including diagnosis and treatment.