Blood Test For Lamblia In Children, When And How To Take?

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Blood Test For Lamblia In Children, When And How To Take?
Blood Test For Lamblia In Children, When And How To Take?

Video: Blood Test For Lamblia In Children, When And How To Take?

Video: Blood Test For Lamblia In Children, When And How To Take?
Video: Collecting blood samples for hemoculture in children with bacterial pneumonia or meningitis 2023, December

What tests for lamblia are prescribed for children, how to prepare?


  • 1 How can you get giardiasis?
  • 2 When do I need to get tested for Giardia in a child?
  • 3 Diagnostic methods
  • 4 Analysis of feces for lamblia and cysts

    4.1 How to get tested correctly?

  • 5 Stool analysis PCR

    5.1 How to get tested correctly?

  • 6 Blood test for Giardia for antibodies

    6.1 How to donate blood for lamblia?

  • 7 Complete blood count

    7.1 How to get tested correctly?

Human parasitic diseases, in particular giardiasis, are quite widespread. Especially often Giardia affects the child's body. This parasite can enter the human body with tap water if it has not undergone a sufficiently effective cleaning procedure.

Giardia can easily survive in soil for up to several months, and can be transmitted with household items. The source of infection is a person in whose intestines this parasite is located, while outwardly the disease may not manifest itself in any way.


Children of preschool age who spend a lot of time in the children's team are at an increased risk group. Through toys, parasites easily pass from child to child, especially if the child has a habit of biting nails or taking objects in his mouth.

In order to minimize the likelihood of infection, kindergartens regularly collect tests to identify all kinds of helminths, including lamblia.

How can you get giardiasis?

Infection occurs through the mouth, parasites penetrate the gastrointestinal tract, settling in the small intestine. Here they are attached to the walls. As a result of their vital activity, there is a violation of the digestive process, disruptions in the assimilation of vitamins, fats, glucose.

The incubation period lasts several weeks after infection. After this, the disease enters the acute stage and, if drug intervention did not occur, it goes into the final, chronic stage.


When do I need to get tested for lamblia in a child?

If a child regularly attends kindergarten and spends a lot of time among a large number of children, giardiasis should be tested at least once every six months. The doctor may prescribe an unscheduled referral for examination if the child's health has worsened and the symptoms coincide with the manifestation of giardiasis.

These symptoms can be as follows:

  • Frequent abdominal pain
  • Stool disorder, most often diarrhea;
  • Vomiting and nausea;

  • Bloating and frequent rumbling in the intestines;
  • Diarrhea can suddenly be replaced by constipation;
  • A thick white coating appeared on the tongue;
  • There was a "marble" pallor of the skin;
  • With giardiasis, the skin often dries and flakes;
  • A rash may appear;
  • The child quickly gets tired, is capricious;
  • Bad sleep;
  • Loss of appetite, which leads to weight loss.

If the child's immunity is strong enough, the disease may not give clinical manifestations, being asymptomatic

Diagnostic methods

There are direct methods and indirect ones. Direct analyzes include stool analyzes for the determination of cysts or vegetative forms of lamblia or their DNA in them and the determination of antigens in them. For indirect - a blood test for antibodies to parasites or for the quantitative content of ROE and eosinophils. The attending physician decides which way to conduct the study.

None of the tests can detect the presence of a disease with one hundred percent accuracy. But complex diagnostics, combining direct and indirect research methods, helps to determine as accurately as possible the presence of the pathogen in the body, and to start treating the child in a timely manner.

Often whole families or groups are ill with giardiasis. Therefore, when diagnosing this disease in one child, it is necessary to conduct a health examination of all family members and children from the team. This will prevent re-infection and allow timely detection of the disease in other children.


After completing the full therapeutic course, re-testing is required. The feces are examined for the presence of lamblia and their cysts, for the presence of DNA. Repeated blood sampling is performed.

To ensure the correctness of the results, analyzes are carried out several times at intervals of several days. Only after receiving all negative results, the child is considered absolutely healthy.

Analysis of feces for lamblia and cysts

Since the parasites live in the small intestine, the study of feces is a mandatory procedure. Thus, you can find not only the giardia themselves, but also traces of their life.

The reliability of this study is about 50%. This percentage is due to the fact that the excretion of parasites and their cysts through the intestines does not occur regularly, but at certain intervals that cannot be calculated.

In order to make a final conclusion on the basis of the analysis of feces that there is no lamblia in the body, it is required to pass the analysis at least three times. The interval between procedures should be 2-3 days. To surely exclude the likelihood of this disease, a control study is prescribed after three weeks.


The result of the analysis of feces for lamblia will be most effective if you know how to properly collect the biomaterial.

How to get tested correctly?

  1. The biomaterial must be liquid. This will make it easier to examine. Otherwise, the result may be false negative;
  2. You need to take morning feces, just before the analysis. If the material was collected in the evening, it is strictly forbidden to store it in the refrigerator. Giardia and cysts die from the cold, which can also affect the effectiveness of the study;
  3. To collect feces, you need to take absolutely sterile dishes;
  4. You need to take feces from several places;
  5. The faster the feces after delivery fall into the hands of a laboratory assistant, the better. After another 20 minutes after collection, live lamblia can be found in the feces, then they die. To detect cysts, feces need to be examined within 24 hours;
  6. You can not take antiparasitic drugs the day before;
  7. If treatment with antibiotics was carried out, they must be stopped 3-4 days before the test.

The laboratory assistant, by means of a multiple magnification of the sample, examines the feces under a microscope, trying to detect lamblia or their cysts. The disadvantage of this study is that the specialist may not notice the presence of parasites and make the wrong conclusion.

If parasites have been detected, the patient is assigned additional studies. The next step is to test the blood for antibodies and diagnose feces for antigens.

Stool analysis PCR

This test for lamblia in a child is carried out in order to verify the presence or absence of the disease. Its reliability is 98%. This test determines if there is DNA in the feces of the causative agent. Polymerase chain reaction (PCR) can detect even one single parasite cell.

In order for the result to be as informative as possible and reflect reality, some rules must be followed.


How to get tested correctly?

  • A few days before the delivery of excrement, they refuse to take laxative tablets, if any. This is due to the fact that the feces must be dense in order to detect lamblia DNA in it.
  • Antibiotics and drugs that can affect the color of feces (medicines containing iron) should be abandoned.
  • The stool sample should be collected in a clean container; it is best to purchase a special container for this purpose in a pharmacy.
  • The jar should be no more than 1/3 full.
  • You cannot receive biomaterial by means of an enema.
  • The feces should be free of foreign matter, including urine.
  • It is best to collect feces just before the study, although material from three days ago is quite suitable for analysis.


Giardia blood test for antibodies

This analysis is indirect. Of course, lamblia in the blood of children does not settle, and this study does not allow identifying the parasites themselves. But this test helps to determine the level of antibodies in the child's blood. According to these indicators, it can be concluded whether the child has giardiasis.

This blood test for Giardia in children is extremely rare, since venous blood is required for this examination. For babies, taking blood from a vein is a complicated procedure. Therefore, the detection of the level of antibodies in young children is rarely carried out, mainly limited to the analysis of feces and a complete blood count.

At different stages of the disease in the body, the content of three groups of immunoglobulins increases: A, M and G. ELISA detects their content, making it possible to conclude that giardiasis is present.


In the first two weeks of the disease, the body actively produces antibodies of the IgM class. It should be borne in mind that immunoglobulin does not begin to be produced from the first day, this may take up to 7 days. Therefore, if there are clear signs of giardiasis disease in a child, but the blood test showed a negative result, additional diagnostics of the body must be carried out.

If, as a result of the study, immunoglobulin M was detected, this indicates that giardiasis is at the initial stage of the disease and no more than two weeks have passed since the invasion.

After two weeks, antibodies of class M are replaced by antibodies of class G. This means that the disease has passed from the initial stage to an acute degree. If the content of the latter is too high, then giardiasis has passed into the last, chronic stage.

A month after infection, the body begins to actively produce antibodies of group A. Their presence indicates that the disease is actively developing.

How to donate blood for lamblia?


Due to the fact that this analysis with a high degree of probability allows detecting parasites in the body, it is still prescribed to children. In order for a blood test for Giardia in children to be as effective as possible, you need to know how to take it.

  • You can not take food less than 11 hours before the analysis;
  • The last meal should not contain a lot of fat and sweetness;
  • Drinking juice and soda is strictly prohibited;
  • You should not drink milk in the evening, this will also affect the results of the study;
  • Blood is taken in the morning on an empty stomach.

A blood test for Giardia in children can give a false negative result if the child's immune system is weak and cannot respond to the disease with sufficient antibody production. This reaction is possible even if there are not too many parasites in the child's intestines.

Remember that the body needs some time to develop antibodies. A negative analysis in the case of clinical manifestations of the disease can only mean that the process of antibody production has not yet begun and no more than 2-3 days have passed after the invasion.


The test result for giardia in children can be positive even when the disease is absent.

Even after the parasites are removed from the body, antibodies are in an increased content. This is due to the fact that traces of vital activity: toxins and poisons are still present in the body.

It may take up to six months to fully recover the body after an illness. All this time, the analysis for the content of antibodies will show an increased content of immunoglobulin G.

General blood analysis

Just like the previous study, this method refers to indirect, it does not directly detect the causative agents of giardiasis, but by the reaction of the body it helps to suggest whether the child has this disease. Unlike the ELISA study, in this case, blood is taken not from a vein, but from a finger, so this analysis is more realistic in young children.

The essence of the study is to determine the level of ROE and eosinophils (a subtype of leukocytes). By their number, it is possible to conclude about the presence / absence of the pathogen in the body.

How to get tested correctly?

In order for the results of the analysis for lamblia to be of the highest quality, you need to know how to donate blood to a child.

  1. Blood sampling is carried out in the morning on an empty stomach, while the last meal should be at least 10 hours before the procedure.
  2. You cannot take this test if the child is sick with colds, otherwise the results can be misinterpreted.
  3. A week before the analysis, you need to stop taking antibiotics, if this was done, taking antiparasitic drugs is also prohibited.


In the presence of giardiasis, this analysis will necessarily determine an increase in eosinophils, such a deviation from the norm occurs as a result of the presence of parasites in the body of children. But we must not forget that this reaction is also likely in case of an allergic reaction to something.

The rate of eosinophils in children is different depending on age. In babies under one year old, this figure is 1-5% in relation to leukocytes. In children under two years old, the normal content of eosinophils increases to 7%. From two to five years, the parameter of the norm is 1-6%. In children over the age of six, the norm rate ranges from 1 to 5%. In the event that there are lamblia in the child's body, the indicator rises by 20%.

Based on the results of a general blood test, it is impossible to unequivocally conclude that there are lamblia in the child's body, but in combination with the study of feces, it allows the child to make such a diagnosis as giardiasis.