Blood test for tuberculosis: features, types and transcription

Many are interested in how the blood test for tuberculosis is taken and is being done. This procedure is quite common. This is a modern answer to previous types of diagnosis of the disease. But what are the blood tests? What kind of features do they include? And as a citizen, by results, he must understand whether he has a disease, or not? It is not so difficult to understand all this as it seems. You do not need to have a medical education so that you can infer from the results. So what kind of knowledge should a citizen have regarding TB tests?

About the disease

First, we will analyze what kind of disease is involved? The thing is that tuberculosis is a serious chronic disease, extremely dangerous and contagious. Transmitted by airborne droplets or through household appliances. It is very common in the world, but in the early stages of tuberculosis it is difficult to identify.

This disease can affect all human organs. Therefore, one can not accurately predict what the outcome will be. In order to recognize the disease in time, it is required to conduct a complex of studies. For example, to make a blood test for tuberculosis.

The most common type of disease is the one that affects the lungs. It is with him that many have an association. Quite often the manifestation of the disease can be confused with a common cold. Tuberculosis itself is not seriously manifested. Especially at the initial stages of development.

Types of diagnosis of the disease

Many are interested in the name of the blood test for tuberculosis. Knowing this is important. After all, with timely treatment, the disease recedes, and the person does not face serious negative consequences of the disease. It is important to know that at the moment there are several types of diagnostics in the world.

Which ones? The following can be distinguished:

• Mantoux test;
• Sputum analysis;
• Bronchoscopy;
• EIA;
• QuantiFERON-TB Gold;
• IGRA;
• PCR.

In some cases, a general blood test is performed. Usually this is done in the initial stages to reveal the probability of the presence of the disease. A confirmation occurs only through the methods mentioned earlier. Now we have come up with another way, which replaces the blood test for tuberculosis - a diaskintest. He does not come into contact with the blood, but it helps to detect the tubercle bacillus in the human body. It has a number of advantages and disadvantages. In Russia it was introduced in 2016.

ELISA

Now a little bit about the blood tests. After all, they are considered the most informative. Most often, this term means an ELISA test. Such a blood test for tuberculosis can reveal the presence of antibodies to tubercle bacilli.

In principle, not the worst option. All that a patient has to do is give blood to the analysis. Usually take venous, it provides a more accurate result. Unfortunately, now it is accepted to consider IFA as not very informative. After all, this study can not tell at what stage the disease is, if it exists. But this procedure helps, as already mentioned, to identify the presence of antibodies to the disease in the body.

Fortunately, medicine does not stand still and there are other ways to identify the disease. And, connected with blood. What are the pros and cons of them? How are they conducted? How can you understand that a person is sick?

PCR diagnostics

It is much more informative and effective to analyze the blood of PCR for tuberculosis. This is a modern method that allows you to determine the presence of a tubercle bacillus. Extremely informative, if the study does not take blood, but sputum.

As a rule, PCR diagnostics is prescribed for suspicious symptoms that resemble tuberculosis in some way. Nevertheless, as doctors say, this study in the case of blood does not give 100% of the result. It is possible only when the patient is sick with tuberculous sepsis. Otherwise, PCR-diagnosis of blood does not have high effectiveness.

Mantoux

What else should I pay attention to? As a rule, the blood test for tuberculosis in children is not carried out. Most often they are assigned the so-called Mantoux reaction. This technology allows to detect the presence of the disease with high, but not 100% accuracy.

How is the analysis done? A subcutaneous method is administered to the child with a special drug. Next few days you need to watch the place of injection. If there is no tuberculosis, then this area will remain unchanged. You can notice only a slight swelling and discoloration of the skin - it will become more pink.

In the presence of tuberculosis, the site of the injection swells, swells, the tumor begins to expand. Sometimes can get cyanotic color. In this situation, the child is re-appointed Mantoux. Either a blood test for tuberculosis (ELISA or PCR) is done, which confirms or refutes the result of the test.

Mantoux is sometimes mistaken

Nevertheless, it should be noted that the Mantoux reaction is not the best way to diagnose tuberculosis in the body. The thing is that this analysis is often mistaken.

How else can you interpret the analysis? Deciphering the positive Mantoux reaction is simple. It can be observed when:

• Exacerbation of common chronic diseases;
• Asthma;
• Allergies;
• Infectious diseases;
• Weakened immunity;
• Epilepsy.

Accordingly, even a positive sample does not give an accurate indication of the presence of the disease. Therefore, a blood test for tuberculosis instead of Mantoux is more effective and informative. It is necessary to exclude all previously listed variants of the development of events. Only then it will be possible to judge the presence of the disease.

General blood analysis

If Mantoux was positive, do not panic. It has already been said that this method of diagnosis is not the best. You need to take a blood test. With pulmonary tuberculosis (and not only), there are some changes in the body. Which ones?

It's all about the fact that at the initial stages the blood remains unchanged. Therefore, general or clinical analysis does not make sense. Depending on the "neglect" of the disease, these or other indicators will change. A common blood test for tuberculosis sometimes really helps to make sure the presence or absence of the disease.

Nevertheless, only it should not be relied upon. After all, the blood and its composition vary, depending on many factors. Therefore, it is recommended that either ELISA-diagnostics or PCR. But also about the general analysis of blood, too, should not be forgotten.

Decoding by general analysis

What indicators should I look for if there is a possibility of tuberculosis infection? With an active stage of the disease, a general blood test will really help to understand that the pathogen is in the blood.

How exactly? Fundamental is the ESR. Normally, this indicator will depend on the person's age. The following data should be used:

• Children under 10 years - up to 10 mm / h;
• Women under 50 years - up to 20 mm / h;
• Women after 50 - up to 30 mm / h;
• Men under 50 years - 15 mm / h maximum;
• After 50 - up to 20 mm / h.

Nevertheless, ESR in pregnant and sick people can increase. With tuberculosis, as a rule, this indicator increases to approximately 50 units or more. Therefore, you should pay attention to it. If the rate of erythrocyte sedimentation in the blood exceeds a significant norm, we can conclude that the probability of infection is high.

Features of the blood test

What features should be considered if it is decided to conduct an additional study for the presence of the disease being studied? The analysis of blood for tuberculosis is often used instead of Mantoux. But at the same time, ELISA and PCR are often not enough for the final diagnosis. The general analysis of the blood also does not fully show the picture of what is happening in the body.

It should be noted that the doctor prescribes a biochemical blood test when suspicions of the presence of a tubercle bacillus in the body. You can also do a separate study for the presence of protein. This will make sure the results.

If there is TB, but only in an inactive form, then the protein index will be in the redistribution of the norm. The acute form of the disease increases cholesterol, urea and lysozyme. Thus albumin appears to be lowered.

A disease that affects the liver increases such indicators as AST, ALT and bilirubin. All this is revealed by the analysis of blood, while the Mantoux reaction does not give such information. This fact must be taken into account.

Diaskintest

Now it is clear that if there are any concerns about the presence of the studied disease in the body, you can take a blood test for tuberculosis. Biochemistry and general research are also additionally assigned. All this helps to comprehensively assess the situation and conclude that there is a disease in the body.

Nevertheless, many people now talk about a new type of tuberculosis diagnosis, which allows not to contact the reagent with blood. It is a question of the previously mentioned diaskintest. This is a replacement for Mantoux. Is it worth to believe this study? What are the pros and cons of it?

This method of diagnosis allows you not to contact blood - this has already been stressed repeatedly. So, with a weakened organism, there is no probability of contracting the disease. For the patient, the dyskintest resembles Mantoux. The study is required to be conducted annually. Usually every 12 months for people from 8 to 17 years.

True, many point out that this type of body check for tuberculosis is not accurate. All this is due to the fact that, like in the Mantoux reaction, some factors can give a false positive result. And the person will be given either a repeat examination or a blood test for tuberculosis.

Conclusion

Now it is clear how it is possible to identify the presence of the studied disease with the help of certain analyzes. QuantiFERON-TB Gold and IGRA are rare in practice blood testing techniques. The screenshots are available, which indicate the content of antibodies and the presence of the disease. In Russia they are practically not applied.

It can be noted that even general and biochemical blood tests will help to identify tuberculosis in one or another case. It is enough to pay attention to some indicators. They will be violated. ESR in tuberculosis necessarily increases. In general, only a doctor can make an accurate conclusion on the basis of several studies. To confirm the diagnosis, you can take a blood test instead of a sputum sample.