Diagnosis of polio: basic methods, tests. Why is polio dangerous?

Interpretation of results

It is advisable to take a test for lgA antibodies if there is a suspicion of a currently asymptomatic course of the disease or a recent infection. In the latter case, at least 2 weeks must pass from the time of recovery.

Detection of type A antibodies can be a sign of both current and recent illness. To confirm a current infection, you should take a swab test for coronavirus.

When taking a comprehensive test for lgA and lgG antibodies, the results can be of 2 types:

• The detection of only antibodies A in the absence of immunoglobulins G suggests that the person is sick now.
• The presence of both types of antibodies means that the infection has already left the body and the patient is healthy.

If a quantitative analysis was carried out, then the result is lgA>1.1. Borderline numbers - lgA = 0.8-1.1 - require re-testing, since if this is an early stage, antibodies may not have yet been developed in sufficient quantities.

There are characteristic symptoms to confirm the disease, and the diagnosis must be confirmed by taking a nasopharyngeal swab. If the result is positive, the antibody A level will rise after 2 weeks.

Attention! lgA is the earliest indicator and is considered more accurate than lgM due to its greater specificity.

Antibodies are large specific proteins that are secreted by immune plasma cells to fight pathogens, protein toxins and various foreign agents.

An IgA antibody test may give a negative result when the coefficient is less than 0.8. This means that there are no antibodies of this type, because there was no contact with the virus, or the disease is just beginning, and the immune response will appear later. If you have symptoms of coronavirus, you must take a PCR test.

polio antibody test

I have been working on this topic for more than 20 years. And as a school nurse, who noticed too many “inconsistencies” in ordinary vaccination activities for children from 7 to 16 years old (more than 2,500 schoolchildren went through me). And as a mother of four children and a “house doctor” for her many nephews, and now for her grandchildren. I'll start with the main thing.

The immune (protective) system of every person is one of the most complex, multicomponent and subtle systems of our body. It is common knowledge that each person reacts differently to any bacteria or virus; Each of us experiences illness, blood transfusion, surgery differently...; Everyone’s body recovers from such stress in its own way... That is. our immunity has to solve a lot of different problems - from “allergic reaction” to ... “carrying a child”! And this happens very individually. The formation of our immunity (which is not a “constant value”) is influenced by many factors, including our lifestyle, stress, illness, our own microflora, and... vaccinations. As you know, vaccination means the SPECIAL introduction of any antigenic material into the body (in the form of a vaccine) - in order for the BODY TO DEVELOP ANTIBODIES to this disease. Then the repeated encounter with this infection occurs more calmly: the person either does not get sick or tolerates this disease quite easily. This is a generally accepted description of the effect of a vaccine (what is expected from it). Artificial vaccinations (like antibiotics) are an important achievement of our science. So I treat them with respect. However, I just can’t agree with the vaccination SYSTEM that now exists in our country. I will try to explain my current attitude towards vaccine prevention (i.e. the prevention of infectious diseases with the help of vaccines), based on my own experience and the information available to me. So, in my experience - including 7 years of experience working in a school medical office (more than 1800 children), where the main work was to cover children with vaccinations and the Mantoux test - there are two different approaches to parents on the issue of vaccinations: 1. “Let specialists decide when and what vaccinations to give - they know best.” These are the majority of parents and they completely trust doctors. 2. “We want to figure this out ourselves” - such parents demand detailed explanations from specialists for each planned vaccination. Most often, such parents refuse vaccinations or get them according to an individual plan. I myself went through different stages of my relationship with vaccinations. While studying at medical school, I was more inclined to approach No. 1. And I argued with BP about the need for vaccinations... Moreover, the disease was Diphtheria! Tetanus! Polio! - who wants a child to get sick from them?! Why not vaccinate?! - that’s what I thought... However, life forced me to lean more and more towards approach No. 2 - too many questions arose that none of the doctors could intelligently answer. Discussing these issues in our clinic was not welcomed, and discussing this with the “uninitiated” was considered unacceptable - they say, what can “non-medics” understand?! In addition, working “inside” the state system of preventive medicine, there was simply no time to object, find out, or prove anything: everything was established, worked out - records, reports, figures, percentages... - just keep up! Over time, a lot of questions and “inconsistencies” regarding vaccination have accumulated in my practice. I'll tell you about a few.

Semi-quantitative tests: reference values

• lgM
• logM=1-2, logG
• lgM≥2, lgG
• lgM
• logM≥1, logM≥10. The result is questionable: the coronavirus may remain in the blood or may already leave the body. The best solution is to repeat the test after a week.

Attention! Deciphering antibodies to coronavirus in accordance with the specified values ​​is recommended by the Moscow Department of Health.

How many antibodies should people have: norms

Forms of the disease

When discussing the diagnosis of polio in children and adults, it is necessary to make a reservation that the notorious differentiation is always carried out on the basis of symptoms. And each form of the disease is individual. The following list can be distinguished:

• Meningeal form. Manifestations: severe pain, tense roots of the spinal nerves and nerve trunks, their pain on palpation.
• Spinal shape. Manifestations: gentle, non-paretic gait, preservation of muscle tone, discomfort in the joints during passive movements, increased deep reflexes, inflammatory changes in the blood. This disease is often confused with polyradiculoneuritis, diphtheria polyneuropathy, and Werdnig-Hoffmann spinal amyotrophy.
• Poliomyelitis form. The pathological process is diagnosed in the cervical segments. Manifestations: paralysis of the muscles of the shoulder girdle and neck, flaccid paresis, lymphocytic pleocytosis (minor, 40-60 cells), increased protein levels (approximately 0.66-1.0 g/l). When studying the material being studied in the laboratory diagnosis of polio, doctors take into account the epidemiological history. This could be drinking raw milk, being bitten by a tick, etc.
• Diphtheria form. Manifestations: symmetry of lesions, slow increase in paresis over several weeks, detection of disturbances in bioelectrical activity during electroneuromyography. Diagnosed 1.5-2 months after diphtheria.
• Polyradiculoneuritis. Manifestations: slow development and further increase in symmetrical paresis, sensitivity disorder of the radicular and polyneuritic types, increased amount of protein in the cerebrospinal fluid.
• Pontine form. Manifestations: decreased taste sensitivity for salty and sweet, lacrimation on the affected side, pain in the trigeminal points felt upon palpation, disturbances in facial sensitivity and spontaneous pain.
• Bulbar form. Manifestations: convulsive syndrome and deep disturbances of consciousness. It is important to differentiate it from stem encephalitis.

Within the framework of the topic concerning the differential and microbiological diagnosis of poliomyelitis, it must be noted that lesions of the nervous system, which are clinically no different from the disease in question, are often caused by enteroviruses of the Coxsackie-ECHO group. In such cases, the entire range of serological and virological diagnostic methods and the previously mentioned PCR method are used.

What amount of antibodies is considered sufficient?

The answer here is very simple - an IgG higher than the reference value indicates a previous illness and the presence of immunity to coronavirus infection. This value for Sars-CoV-2 is 10.0.

Today, several testing methods are used to determine antibodies in the blood - these are, first of all, rapid tests and enzyme-linked immunosorbent assay (ELISA). Rapid tests can be compared to home pregnancy test strips

The presence of type G antibodies in the blood means that immune cells have recognized the virus and the response process has begun. The digital parameter shows how pronounced the immune response is. Reference values ​​are obtained through mass testing of a healthy population.

In the vast majority of Russian test systems that use the ELISA and CLIA methods - enzyme-linked immunosorbent assay and chemiluminescence immunoassay - the reference IgG values ​​are 10.00. But there are also those where they are equal to 2.5.

Attention! When taking the test, it is better to clarify what the reference value is so as not to make a mistake in decoding.

Thus, the antibody count is considered good if it is higher than or equal to the reference values.

Interpretation of quantitative IgG tests:

The maximum value of the level of type G antibodies is an indicator of the high resistance of immunity. If it is more than 15, we can talk about some protection from re-infection. However, the connection between these parameters has not yet been reliably established, and it is impossible to say how long this protection will last.

If your IgG is more than 100, you can even become a plasma donor and donate your blood to seriously ill Covid patients. In some laboratories this threshold is even lower and amounts to logG=40.

Poliomyelitis and vaccination

According to statistics from the World Health Organization, almost 10 million people who have had polio suffer from paralysis to one degree or another. In the last decade, significant progress has been made in stopping the spread of the virus. Polio case data from health ministries around the world has dropped tenfold. The population's immunity is strengthened thanks to mass vaccination against a dangerous infection.

The recommended age for vaccination is from 3 months to 3 years. In Russia, according to the immunization plan, almost 99 percent of children were vaccinated against polio. The figure is unique, especially considering the fact that the overall world statistics in a combined percentage reached only 74. The country has created a system for registering paralysis as a result of polio.

Planned explanatory and preventive work is carried out on all social categories of the population. Particular emphasis here is placed on educating young parents about the importance of protecting children's immunity. Many of them, exposed to the erroneously common belief that vaccinations are harmful to infants, simply deny them immune protection. Fortunately, cases of such carelessness are rare and most parents agree to vaccination.

Where to take the test

You can test for the presence of antibodies in private medical laboratories Gemotest, Dialine, Invitro, Helix, CMD, Medsi, etc. You just need to call the multi-line phone number listed on the website and find out where the nearest office is located.

Attention! We have written in detail about the features of blood testing for antibodies at the CMD Center for Molecular Diagnostics here.

In the near future, it is planned to launch mass testing using test systems from the Vector State Scientific Virology Center. The price of tests is from 600 to 1900 rubles.

Mass testing has already been launched in Moscow and St. Petersburg, now it’s the regions’ turn

If desired, you can do a rapid test using an accelerated method. The result will be less accurate, but faster. It is obtained in a few hours or a few minutes, depending on the type of device.

If a plastic panel is used, then a drop of blood is dropped into its window, and 1,2 or 3 stripes are displayed nearby:

• 1 – no antibodies;
• 2 – active stage of the disease;
• 3 – recovery.

These rapid tests can be performed outside of laboratory conditions - at home, in a doctor's office, at an airport and other places. More fundamental studies require blood sampling from a vein and analysis using the ELISA method - colored antigens are added to the sample, which, when combined with antibodies, change its color.

To perform a quantitative analysis and determine the rate of antibody production, the blood is diluted with saline, and part of the mixture is poured into a test tube with a reagent. The concentration is then adjusted by gradually diluting the mixture until a reaction is visible.

Tips on how to properly prepare for research

Tip #1

2-3 hours before donating blood, you should not eat, but you can drink still water.

Tip #2

It is advisable not to smoke half an hour before the procedure.

Tip #3

Even if IgG antibodies are detected, you should not “relax”, since the connection between their presence and the formation of stable immunity to coronavirus has not been fully established. You must continue to wear a mask and follow generally accepted precautions.

Tip #4

You can’t go get tested if you have a cold, since signs of ARVI are a contraindication to the test.

Tip #5

Immunoglobulins type M can be detected before the infection has multiplied in sufficient quantities to be detected by a PCR test. And also before IgG antibodies appear. That is, using this indicator, a preliminary diagnosis can be made during periods when diagnosis is difficult.

Tip #6

Evaluation of the results of a blood test for antibodies is possible only taking into account the indicators of the PCR smear.

Tip #7

If the result is borderline and in doubt, then it is recommended to retake the test in about a week.

FAQ

Can there be no antibodies if you have had coronavirus? There is not and cannot be an exact answer, since the coronavirus infection has not yet been sufficiently studied, and there is little statistical data, and what exists is sometimes contradictory and inconsistent.

The algorithm for counteracting viruses is standard; the main role in it belongs to antibodies

However, the absence of antibodies after Covid-19 is quite acceptable for several reasons, which include:

• misdiagnosis of coronavirus initially. This situation is not uncommon;
• the error of the antibody test itself, which simply did not work;
• low immune status of the patient, for example, with AIDS: the person coped with the infection, but weak immunity did not “remember” the pathogen and did not produce enough antibodies;
• immunity to Covid-19 has developed, but only for the duration of the illness. After defeating her, the synthesis of protective globulins stopped as unnecessary.

What can affect the result of the analysis? The study can show the absence of IgM if it is present during the so-called “serological window” - between 5-7 and 10-14 days in case of indolent disease. In this case, the PCR test will also give a negative answer, since the virus has not yet multiplied to a detectable level.

It also happens the other way around, when tests show the presence of IgM, but in fact there is no Covid in the blood. This result is possible in patients suffering from systemic lupus erythematosus, thyroiditis and other autoimmune pathologies, as well as HIV infection.