HBsAg, qualitative test (HBs antigen, hepatitis B surface antigen, Australian antigen). Hbsag negative anti hbs positive

An HBsAg blood test is an important test that most of us make sense to have from time to time. It confirms or refutes the presence in the blood of antibodies to the hepatitis B virus, one of the most insidious infectious diseases of our time.

HBsAg - what is it?

The word “hepatitis” itself means an inflammatory disease of the liver. It occurs for several reasons. Among them are viruses that enter the body in various ways. The most common and dangerous pathogens of this disease include the hepatitis B virus, which the World Health Organization recognizes as a global problem for the population of the entire globe.

It's important to know!
Hepatitis B in the chronic stage in 20-30% of cases leads to the development of cirrhosis of the liver or cancer of the gland in patients.

The disease begins from the moment the virus enters the bloodstream: this occurs due to unprotected intercourse, the use of non-sterile medical instruments or hygiene items (toothbrush, comb, razor) of a sick person. The hepatitis B virus is DNA surrounded by a protein capsule called a capisdom. The latter is responsible for the process of introducing the virus into the cells of the human body. The capsid proteins have been named HBsAg (abbreviation for hepatitis B surface antigen), HBcAg (hepatitis B core antigen), and HBeAg (hepatitis B capsular antigen). By their presence in the patient's blood, it can be assumed that the person is infected with the virus, so the analysis for the presence of these antigens, and primarily HBsAg, is the standard method for diagnosing hepatitis B.

The advantage of this analysis is that the HBs antigen is determined in human blood as early as 4–5 weeks after infection, while the incubation period for hepatitis B is up to six months. Thus, timely diagnosis allows starting treatment long before the first manifestations of the disease, minimizing damage to the patient's liver and preventing further spread of the infection.

When is an HBsAg determination necessary?

Hepatitis B can be contracted by anyone who has not been vaccinated against the disease. Therefore, checking the blood for HBsAg at least once every few years is useful for all unvaccinated people, even if there are no apparent reasons for concern.

• medical workers;
• pregnant women (hepatitis B is almost always transmitted to the child from an infected mother);
• children born to women carriers of the virus;
• people with symptoms or laboratory evidence of any disease of the liver and biliary tract;
• patients referred for hospitalization or surgery;
• blood and organ donors;
• family members of patients with hepatitis B;
• people with chronic diseases who frequently use medical devices that come into contact with blood (for example, patients with kidney failure who regularly undergo hemodialysis);
• drug addicts;
• people who are about to get vaccinated against hepatitis B.

Warning signs to check for hepatitis: unexplained fever, insomnia, prolonged indigestion, jaundice and pruritus, joint pain and rash, feeling of heaviness or pain in the right hypochondrium.

It's important to know!
The hepatitis B virus is incredibly resilient. It is resistant to boiling and freezing, and at room temperature it is stored in a dried drop of blood, on a razor or in a used syringe for up to several weeks. It can be destroyed only with the help of special sterilizing substances or by prolonged heating. Even in people who have been treated for hepatitis B, the virus remains in the blood for the rest of their lives in most cases. Therefore, it is important to get tested for HBsAg whenever transmission is suspected.

It is very difficult to "catch" a virus in a person's blood. Therefore, doctors use the so-called infection markers, which include HbsAg. In response to its appearance, the body's immune system produces special substances - antibodies that fit foreign proteins like a key to a lock. Many tests for hepatitis B are based on the principle of this interaction: a small amount of blood, which is taken from the patient's vein on an empty stomach, is added to a dye reagent containing ready-made antibodies to HbsAg. And if an antigen is present in the analysis, then the laboratory assistant will see a change in the color of the sample (this type of research is called ELISA, or enzyme immunoassay).

There are two types of blood tests for the carriage of the Hbs antigen: qualitative and quantitative. The first one is the most common. It is used to obtain an unambiguous answer about whether a person has hepatitis B antigens in the blood. Quantitative analysis allows you to determine the concentration of a foreign protein in the human body. This indicator is necessary to determine the stage of the disease and evaluate the effectiveness of treatment. Preparation of HbsAg test results takes from several minutes to one day, depending on the reagents used and the speed of the laboratory.

In the case when the analysis turns out to be positive, the doctors immediately conduct a duplicate study, so as not to be mistaken with the conclusions in any case. Sometimes a second test does not confirm the reliability of the first result: this can happen due to the individual characteristics of a person's immunity. Then the patient is given a conclusion: "the result is repeatedly positive, unconfirmed." This means that after some time the analysis must be repeated, and using a different laboratory method.

Norm of antigen in the blood

Fortunately, most people who have a qualitative HbsAg test have a negative test result. Usually this is enough to remove the suspicion of hepatitis B infection. Therefore, people who are being tested for the first time or whose results of all previous tests were negative are prescribed a qualitative analysis - it is faster, cheaper and easier to perform.

But if his results were positive and in cases where a sick person is already being treated for hepatitis B, the doctor gives a direction for quantitative HbsAg. During such diagnostics, the laboratory confirms the presence of the virus in the human body and indicates the concentration of antigens in the patient's blood.

The unit of measurement in this case is the number of international units per milliliter of blood (IU / ml). If the quantitative analysis shows less than 0.05 IU / ml, the result is considered negative. This may indicate a person's recovery, the transition of the disease to a latent form, an error in the first, qualitative, test, or, in rare cases, a fulminant course of hepatitis B (while the symptoms of the disease are obvious).

If a person's blood contains more than 0.05 IU / ml of the antigen, the result of the analysis is considered positive (it is also rechecked using a confirmatory test). By comparing the values ​​obtained with the previous quantitative blood test for Hbs antigen, the doctor concludes how the disease proceeds and whether the prescribed treatment is working.

HBsAg "positive"

A positive HBsAg test is always a reason to see a doctor. Only after examining the patient, the specialist concludes whether the person is a carrier of hepatitis B (when the infection does not manifest itself, but the virus can be transmitted to other people) or whether the disease is in an acute or chronic stage. In the event that the laboratory issued a “repeated positive unconfirmed” result, the doctor will help to understand the reasons for this phenomenon.

A positive test result for hepatitis B is not a death sentence. But such news cannot be ignored either. If you took the test on your own initiative or as part of a physical examination, sign up for a consultation with a local therapist (or a pediatrician if HBs antibodies are detected in a child). If necessary, he will refer you to an infectious disease specialist.

The treatment plan for hepatitis B depends on the stage of the disease. In the presence of severe symptoms, the patient will be offered hospitalization, but usually therapy takes place on an outpatient basis. Unfortunately, it is not always possible to destroy the virus, so patients for many years must take drugs that suppress the reproduction of the pathogen in the body and maintain liver health.

HBsAg not detected: what does it mean?

A negative HBsAg test result indicates that there is no hepatitis B virus in the blood. But if you are or have recently been diagnosed or treated with products containing mouse antibodies or heparin, the test results may be skewed. In this case (if it is important for you to get information about a possible infection), consult your doctor about when is the best time to do a second analysis.

A successful outcome of the diagnosis is a good reason to think about the prevention of hepatitis B. The most reliable method of protection against this virus, according to WHO, is vaccination. It is recommended to absolutely all healthy people without contraindications to vaccinations.

In addition to the vaccine, simple rules will help prevent infection:

• use only disposable syringes at home, and undergo diagnostic, cosmetic and treatment procedures only in trusted medical centers and companies licensed to provide the corresponding type of service;
• refrain from casual sex and always use a condom if you are not sure that your partner is healthy;
• if you accidentally get blood from a stranger, be sure to take a shower and change clothes (and also get tested for HBsAg after 4-6 weeks);
• take extra care at home if someone in your family has hepatitis B or is a carrier of the infection.

Where can I get an HBsAg test?

HBsAg tests are done in both public and private laboratories. In the first case, we are talking about a check-up on the basis of a polyclinic, a hospital or a specialized medical center - there, diagnostics are usually carried out as directed by a doctor, free of charge if there is a compulsory medical insurance policy. The advantages of private laboratories include the ability to get results faster, and, if desired, to be examined anonymously.

However, only a few companies can boast such high diagnostic accuracy. One of these is an independent network of laboratories "INVITRO". Its employees use test systems from the world's leading manufacturers for analysis, and the results of the studies carried out here are recognized by all medical institutions in Russia. 700 INVITRO offices serve patients in more than 300 cities of our country, in Ukraine, Belarus and Kazakhstan. The company serves about 19 thousand people daily.

It is possible to check blood for HBs antigen on weekdays and weekends, having received an answer the very next day (and if express diagnostics is necessary, after 2 hours), and the form with the results does not have to be taken from the laboratory, it can, at the request of the client, send by e-mail or tell by phone. The high level of INVITRO work quality ensures the reliability of the analysis, which is extremely important in the diagnosis of viral hepatitis B.

Wednesday, 03/28/2018

Editorial opinion

According to Russian laws, any laboratory is obliged to report all positive results of qualitative and quantitative tests for the HBs antigen to the State Sanitary and Epidemiological Supervision Service, which, in turn, reports the identification of an infected person to a doctor in a polyclinic at the place of residence. It is possible to get tested for hepatitis B anonymously, but such a test cannot be used to receive treatment or hospitalization.

Everyone heard. To determine this viral disease, there are a number of tests that can detect antibodies to hepatitis B antigens in the blood.

The virus, entering the body, causes its immune response, which makes it possible to determine the presence of the virus in the body. One of the most reliable markers of hepatitis B is the HBsAg antigen. It can be detected in the blood even at the stage of the incubation period. A blood test for antibodies is simple, painless and very informative.

Hepatitis B markers: HBsAg marker - description

There are a number of markers of viral hepatitis B. Antigens are called markers, these are foreign substances that, when they enter the human body, cause an immune system reaction. In response to the presence of an antigen in the body, the body produces to fight the pathogen. It is these antibodies that can be detected in the blood during analysis.

To determine viral hepatitis B, antigen (surface), HBcAg (nuclear), HBeAg (nuclear) are used. For a reliable diagnosis, a number of antibodies are immediately determined. If HBsAg antigen is detected, we can talk about the presence of an infection. However, it is recommended to duplicate the analysis to eliminate errors.

The hepatitis B virus is complex in its structure. It has a core and a fairly strong shell. It consists of proteins, lipids and other substances. The HBsAg antigen is one of the components of the hepatitis B virus envelope. Its main task is the penetration of the virus into cells. When the virus enters the cell, it begins to produce new DNA strands, multiply, and the HBsAg antigen is released into the blood.

The HBsAg antigen is characterized by high strength and resistance to various influences.

It is not destroyed by either high or critically low temperatures, and also does not lend itself to the action of chemicals, withstands both acidic and alkaline environments. Its shell is so strong that it allows it to survive in the most adverse conditions.

The principle of vaccination is based on the action of the antigen (ANTIbody - GENeretor - manufacturer of antibodies). Either dead antigens or genetically modified, altered ones that do not cause infection, but provoke the production of antibodies, are introduced into the blood of a person.

To learn more about hepatitis B, watch the video:

It is known that viral hepatitis B begins with an incubation period that can last up to 2 months. However, the HBsAg antigen is already released at this stage and in large quantities, so this antigen is considered the most reliable and early marker of the disease.

HBsAg antigen can be detected already on the 14th day after infection. But not in all cases, it enters the bloodstream so early, so it is better to wait a month after a possible infection.HBsAg can circulate in the blood throughout the disease exacerbation and disappear during remission. You can detect this antigen in the blood for 180 days from the moment of infection. If the disease is chronic, then HBsAg may be present in the blood all the time.

Diagnostics and appointment for analysis

There are several methods for detecting and antigens in the blood. The most popular methods are ELISA (enzymatic immunoassay) and RIA (radioimmunoassay). Both methods are aimed at determining the presence of antibodies in the blood and are based on the antigen-antibody reaction. They are able to identify and differentiate various antigens, determine the stage of the disease and the dynamics of infection.

These analyzes cannot be called cheap, but they are very informative and reliable. You only need to wait 1 day for the result.

To be tested for hepatitis B, you need to come to the laboratory on an empty stomach and take it. No special preparation is required, but it is recommended not to abuse harmful spicy food, fast food, alcohol the day before. You can not eat 6-8 hours before donating blood. A couple of hours before visiting the laboratory, you can drink a glass of water without gas.

Anyone can donate blood for hepatitis B.

If the result is positive, then medical workers are required to register the patient. You can take the test anonymously, then the patient's name will not be disclosed, but when contacting a doctor, such tests will not be accepted, they will have to be retaken.

HbsAg positive in the analysis for hepatitis indicates the presence of a specific antigen in the body. Identification of the component is carried out through express diagnostics and laboratory tests. An HbsAg blood test is done to detect the B virus in the body. It affects healthy tissues and liver cells, disrupting the functional significance of the organ. In the absence of timely therapy leads to the development of oncology.

Causes

The appearance of HbsAg is influenced by many factors. A similar mark in the laboratory test sheet indicates the presence of adapted antigens in the body. They appear under the influence of certain conditions.

When examining biological material for the presence of antigens, the HbsAg level is indicated in the results sheet. This is a designation that includes abbreviations for the proteins of the hepatitis B virus. They are found in the body, putting pressure on the human immune system.

The surface antigen representing the causative agent of hepatitis was named HbsAg. It is considered a disease marker. But to confirm hepatitis, the detection of one antigen is not enough. During the study, markers of hepatitis are taken into account. They indicate the presence of a pathological process, its stage and identify the main pathogen. The interpretation of the analysis is carried out by the attending physician.

The result of the study is interpreted unambiguously: HBsAg is present - infection has occurred, absent - the person is healthy.

A positive response is typical for the following diseases and conditions:

• viral damage to the body;
• chronic or acute stage of an infectious disease;
• previous infection;
• carriage;
• errors.

With a viral infection of the body, an antigen is determined during a laboratory blood test. Its concentration depends on the prevalence of the disease. A similar picture develops in acute or chronic hepatitis. The antigen is able to mutate, which makes it impossible to determine the virus in the body. The nuclear component thus obtained is not detected by routine laboratory testing. In the chronic form of hepatitis, two types of the virus are found in the body.

The immune system is able to respond to the penetration of a pathogenic element into the body. In this case, after complete recovery, the antigen test remains positive for a long time. This is a normal condition that does not require additional action.

The human immune system is capable of destroying pathogenic microorganisms on its own. In this case, a protective response is developed, which is accompanied by an intensive production of antibodies. They are stored in the human body for a long time, which is reflected in the result of the analysis. No negative impact on the general condition is observed.

A person can be a carrier of an antigen, but this does not affect his well-being. A similar picture is characteristic of the chronic form of hepatitis.

According to numerous studies, there is the following version: some types of the virus actively multiply in the human body, but do not seek to attack it. As a result, the patient is a carrier of the antigen and is able to infect others. But this does not affect his own health.

The presented version is considered theoretical. In medical practice, such cases were recorded, but their reliability has not been confirmed. It is possible that a person is a carrier not only of the B virus, but also of other pathogenic microorganisms.

Another reason for the positive result of the analysis is passive carriage. A person is infected, a virus lives in his body, but it is not dangerous. It does not cause complications, it does not affect the general state of health. In this state, the virus is able to live for life. But under the influence of provoking factors, a sharp increase in the number of antigens in the body is not excluded. In this case, a person develops symptoms of the disease, which requires immediate medical attention.

The carrier of the virus is dangerous to the people around. It is capable of transmitting the virus through household items, skin-to-skin contact, and other means. A harmful agent is able to enter the body from mother to child.

A positive result is often associated with an error. The person did not properly prepare, did not follow the rules for donating blood, the laboratory mixed up test tubes with biological material. A failure in the determination of antigens is not excluded, which in some way is considered the norm. The probability of an erroneous result is small, but it remains. Poor-quality reagents can provoke an incorrect answer.

Experts recommend not to abandon the repeated determination of antigens. This is necessary in any case, regardless of the reason why the person is taking the test. Repeated laboratory research guarantees a reliable result.

Under the influence of adverse factors (abuse of addictions, improper preparation, mistake of laboratory assistants), the probability of receiving a false positive answer remains. In the form of results, a person sees the presence of antigens and, without consulting a doctor, begins to look for the best way to fix the problem. Self-medication is accompanied by serious consequences, which is dangerous to health.

If a false positive result is obtained, it is advisable to retake the analysis. Experts recommend that you immediately go to an appointment with a doctor who can decipher the answer. It is forbidden to independently make any attempts to eliminate the problem and treat the disease.

The determination of antigens in the body by the serological method often ends in a false positive result. In order to avoid violations and an incorrect answer, doctors recommend that the viral load be determined in parallel. The procedure is a blood test. Additionally, the levels of liver tests are determined, in the case of a viral infection of the body, they deviate from the norm.

It is recommended to visit an infectious disease specialist who will refer the patient to the fibroelastometry procedure. The technique is aimed at determining the state of the liver, the study of its functional significance, contours and additional indicators. The procedure allows you to get a complete picture of the body.

• pregnancy (the severe course of the period of bearing a child is often accompanied by an increase in liver tests);
• rapid progression of malignant neoplasms;
• severe damage to the body by infectious agents;
• previous vaccination;
• malfunctions in the protective functions of the body.

There is no universal remedy for preventing the penetration of viral agents into the body. Infection occurs under the influence of adverse factors and with a high susceptibility of the organism. A patient with a positive result should not ignore the response received. It is advisable to go to the doctor for detailed recommendations and quality therapy.

A positive response in determining the viral antigen is not a sentence. Modern methods of therapy will help to cope with the problem. Depending on the complexity of the situation, a person will be assigned a certain effect on the body. The patient needs to be regularly examined, donate blood to identify the quantitative indicators of the virus. This action is aimed at correcting the prescribed treatment in order to improve the quality of life of the patient and stop the progression of the disease.

HBV (HBV) infection, otherwise known as hepatitis B, is considered one of the most common viral diseases worldwide. According to WHO, more than 200 million people are carriers of this viral agent. About 2 million patients a year die from a dangerous virus.

Therefore, early diagnosis of liver disease is extremely important for recovery from hepatitis. Among the markers of the virus, the HBsAg antigen is isolated, which helps to identify the disease in time and prescribe the appropriate treatment.

And what is HBsAg, what methods it is detected and how the results of the analyzes are deciphered, we will consider in this article.

The abbreviation HBsAg is the Australian antigen, which is part of the shell of the viral agent that causes liver disease - hepatitis B. It is called Australian because this antigen was first identified in Australia.

The outer shell of HBV consists of a combination of different proteins, each of which performs its own function. HBsAg ensures the absorption of the viral agent by liver cells and adsorption of the virus on the surface of hepatocytes. The antigen exists in the form of different structures, as a particle of the capsid of the virus and as formations that are synthesized by the cells of the infected liver. HBsAg in the bloodstream is always higher than virions (the virus itself).

Like any antigen, HBsAg forms an antigen-antibody response complex of the immune system, that is, it contributes to the creation of specific body immunity in response to an infection. Serological identification of microorganisms helps to identify this complex. HBsAg is the very first antigen that can be detected after infection. Therefore, answering the question of what HBsAg is, one can say not only about part of the virus envelope, but also about the marker (indicator) of the virus in the human body.

HBV is hepatropic and the only one among other viruses that infect the liver, which contains DNA. Its activity in the body is low, but under certain conditions it can increase significantly. This is regulated by age, personal hygiene conditions, the epidemiological situation and the individual susceptibility of a person.

How HBV is transmitted:

• sexual relations in any form (sexual way);
• through items for individual use (household way);
• through the blood: tattoos, piercings, non-sterile syringes, etc. (parenteral route);
• from mother to child during childbirth and breastfeeding (vertical route).

Hepatitis B is rarely transmitted in utero because the virus is too large to cross the placental barrier.

Hepatitis B pathogenesis. The incubation period of the disease has a long period, which averages two months. Before the onset of acute symptoms, there is an intermediate phase called the prodrome.

During this period, body temperature may slightly increase, appetite may decrease, the work of the gastrointestinal tract (loose stools, nausea), and skin rashes may appear. Similar symptoms last from 2 days to 1 month, then the acute phase of the disease begins.

The beginning of the acute course of the disease is the yellowness of the skin and whites of the eyes. During the period of jaundice, disturbances in the work of the gastrointestinal tract become more pronounced. In general, the severity of the disease is individual and does not depend on the concept of the acute phase.

The time interval of pathological processes at this stage of the disease is up to six months. Further, the patient either recovers, or the disease becomes chronic. The consequences if left untreated are severe - hepatitis D, cirrhosis of the liver, carcinoma (liver cancer).

The pathogenesis of HBV can be represented by the following chain:

• liver infection;
• reproduction of viruses, pushing them to the surface of hepatocytes;
• entry of particles and virions into the blood;
• immunological reactions;
• damage to organs and systems;
• the formation of immunity;
• recovery.

The earlier HBV is detected, the sooner you can start treatment, and the less complications from a dangerous disease. The HBsAg antigen is detected in two main ways: rapid diagnostics and serological research method.

The first way is easy to carry out at home with the help of a special device - a rapid test. The second method is more accurate and is carried out exclusively in the clinic, as it requires laboratory equipment.

HBsAg antigen and methods for its diagnosis

The most dangerous complication of hepatitis B is considered to be acute liver failure, which often ends in death. Therefore, any person can be interested in the diagnosis of this disease.

Tests for HBsAg hepatitis are mandatory for the following groups of people:

1. Pregnant women at the time of registration for pregnancy and immediately before the birth of a child (the analysis is included in the screening).
2. Persons who, through their professional activities, come into contact with the blood of people (medical staff, laboratory assistants, and others).
3. In the presence of any form of hepatitis.
4. Patients who need surgery.
5. People with other liver diseases: cirrhosis or disorders in the biliary tract.

Hepatitis HBsAg is detected by a blood test. Depending on the method, blood is taken from a vein (laboratory tests) or a finger (home test). Let's consider each method in more detail.

Express diagnostics. For home research, a rapid test is used, which resembles a pregnancy test. Immunochrome tests can be purchased at a pharmacy at a price of 200-300 rubles. The kit includes a test strip, buffer solution, a special container and a scarifier. The test is fast and easy.

How to do:

• prick a finger with a device for bloodletting;
• squeeze some blood onto the strip;
• drip 3-4 drops of liquid on the blood;
• place in the test in a container and wait fifteen minutes;
• interpret the results.

Laboratory diagnostics. For laboratory studies on HBsAg antigen, blood is taken from a vein. Before the test, you can not eat for 12 hours, so the procedure is carried out in the morning. Blood is taken in an amount of 10 milliliters. Then it settles and is passed through a centrifuge to separate plasma, which will be analyzed for the presence of HBsAg.

Serological identification of microorganisms is carried out by two methods:

• RIA - radioimmunoassay;
• XRF - reaction of fluorescent antibodies.

In order to carry out such analyzes, special equipment and reagents are required. Both research methods make it possible to detect HBsAg antigen even before the onset of the acute phase of the disease. Already 3-4 weeks after infection, it is safe to say about the presence of a viral infection.

Surface antigen of the hepatitis B virus and decoding of tests for its detection

After the tests are completed, they need to be decrypted. The home express method will allow you to see if there is a hepatitis B virus in the blood or not, but will not give an accurate picture of the disease. If the surface antigen of the hepatitis B virus was detected by a laboratory method, the doctor will see the quantitative composition of the antigen and the antibody titer.

Thus, it is possible to say at what stage the disease is, whether the infection is primary or whether an exacerbation of the chronic form of hepatitis has occurred.

Express test transcript. There are two strips on the test: test and control. If one control band appeared, then the hepatitis B virus was not detected. Two developed strips indicate the presence of HBsAg in the blood, which means that we can say that a person has hepatitis B. If only a test strip is visible, then the test is ruined.

Deciphering the results of a laboratory study. If the hepatitis B surface antigen test is negative, then the person is not sick. In the case of a positive result, the quantitative composition of HBsAg is indicated. The result can be interpreted as false positive or false negative. This is possible due to a violation of the order of taking the analysis and research technology, as well as if the reagents are of poor quality.

A positive result can be deciphered by a doctor in several ways:

• carriage (a person is not sick, but there is a virus in his body);
• HBV goes through an incubation stage;
• disease in the acute stage or recurrence of the chronic form.

In addition to the surface antigen of the hepatitis B virus, other markers of viral infection are also analyzed. Each of them completes the overall picture.

Other markers of hepatitis B:

• HBeAg - indicates high HBV activity. This is the core protein of the virus. An increase in the amount of this marker indicates the rapid multiplication of viral agents. An HBeAg test is very important before delivery in women with hepatitis. Thanks to him, the doctor determines the degree of risk of infection of the child at the time of delivery.
• HBcAg - are found only in liver cells with high virus activity. In the blood, antibodies to this marker can be detected. The marker can be detected only with exacerbation of the chronic form of the disease.

There is another way to detect a viral infection of the liver by detecting antibodies in the blood: HBs and HBc. The analyzes also take into account which antigens and antibodies are reactive or non-reactive. A doctor can give a detailed description of the disease only if there is a complete examination of the patient.

A blood test for HBsAg is carried out in order to detect the Australian antigen in the human body, indicating the presence of a disease such as hepatitis B. The disease is very insidious due to the absence of a symptomatic picture in the early stages of development and an extremely negative effect on the liver and the whole body as a whole. A blood test detects the presence of an antigen a few weeks after the virus enters the body, while the first symptoms may appear no earlier than a few months.

1 Characteristics of the virus

HBs antigen is a protein of the hepatitis B virus located on the outside of the cell. As soon as infection occurs, the antigen is identified by the body as a foreign object, and the immune system activates all its protective functions to destroy the pathogen on its own. Getting into the liver with the bloodstream, the hepatitis virus binds to the DNA of cells and begins to multiply actively. It is not possible to detect the antigen immediately after infection, since its concentration in the blood is negligible. The serological method is the most accurate, which allows you to identify the disease at the earliest possible stage of its development - 3-5 weeks from the moment of infection, but in this case, much depends on the individual characteristics of the organism.

During the period of active reproduction, the antigen releases new virus cells into the bloodstream, which leads to a rapid increase in the pathogen. When the body begins to actively fight foreign cells, the virus produces a protective protein - antigen, to resist immunity.

If the human body is not weakened by chronic or acute infectious diseases, the immune system itself will suppress the virus and completely destroy it. At the same time, an infected person will not even suspect that he not only contracted hepatitis, but also managed to recover from it. But such a favorable outcome is rarely observed, since in most people the immune system is weakened by poor ecology, bad habits, and malnutrition.

It is necessary to take a blood test for the Australian antigen regularly, and this is especially true for a certain category of people who are at risk.

2 The need for research

Hepatitis is a very serious disease, which, even if it was cured in the first stages of development, does not go unnoticed for the liver and the whole organism. It is important to understand that not a single person is immune from infection with this type of pathology, therefore it is recommended that all people take a blood test to detect the Australian antigen at least once a year.

• personnel of medical institutions who are in direct contact with infected patients;
• laboratory workers in contact with blood and other biological materials that may contain cells of a pathogenic virus;
• employees of kindergartens, boarding schools and schools;
• patients preparing for surgery;
• people with a history of chronic diseases, especially diabetes mellitus;
• blood donors;
• pregnant women;
• people who use drugs;
• patients with skin diseases or sexually transmitted infections.

The main signs of hepatitis B are yellow skin, colorless feces, dark urine, general weakness of the body, nausea, but they do not always have a pronounced manifestation, especially in the early stages of the disease. The insidiousness of hepatitis is that this disease has a very long incubation period, and more than one month may pass from the moment of infection to the manifestation of pathological symptoms, while the liver will be destroyed, and an infected person may, without knowing it, infect others.

Hepatitis is especially dangerous for pregnant women. An analysis for the detection of the Australian antigen during pregnancy must be taken twice - in the 1st and 3rd trimester. In children born from an infected mother, the analysis is carried out immediately after birth, at 3,6,12 years, and then every year. Some patients infected with hepatitis B have no clinical signs, and the antigen itself does not affect the liver, but such a person poses a threat to others. Testing for the Australian antigen is mandatory for people whose family or immediate environment has cases of hepatitis infection.

3 Preparatory stage

To conduct a study to identify the Australian antigen, venous blood is taken. The analysis is carried out only in the morning, and the less time passes after waking up, the more informative the decoding of the test will be. Before taking blood, it is forbidden to have breakfast, drink tea, coffee, juice. It is allowed to drink a small amount of plain water.

A week or two before the test, it is necessary to adjust the diet, turning out to be from fatty and peppery dishes. The information content of the analysis is affected by the intake of medications, therefore, drug therapy must be abandoned for 10-14 days, if this is not possible, during the analysis it is necessary to inform the doctor which drugs are being taken.

The determination of the Australian antigen is carried out in several ways - ELISA and RIA. Given this fact, as well as the fact that each laboratory has its own specifics for conducting blood tests and the quality of equipment, if an antigen is detected in the blood, you should not panic, you need to repeat the analysis in another laboratory.

ELISA is an enzyme-linked immunosorbent assay that is used to detect the Australian antigen. The essence of this diagnostic method is that a special enzyme is placed in a test tube with biological material, and if an antigen is present, the blood will change its color. The second type of analysis - RIA - a radiological method in which blood cells are marked with a special radionuclide, and when it interacts with a pathogenic virus, it begins to emit gamma and beta rays, and their intensity depends on the concentration of the antigen in the blood.

If the result is positive, which stands for the presence of the hepatitis B virus in the blood, the analysis must be retaken. To clarify the primary diagnosis, the polymerase chain reaction (PCR) method is used. This diagnostic method of blood testing allows you to identify the DNA of a pathogenic virus. This blood test is the most accurate way to detect Australian antigen.

4 Results

The interpretation of the analysis is interpreted as positive or negative. In the absence of a pathogenic virus in the body, blood diagnostics will show a negative result, respectively, if a person has been infected, the analysis will be positive. All people are carriers of most viruses of various diseases, which, in a normal state of health and in the absence of provoking factors, do not pose a threat.

Hepatitis B is no exception, therefore, when deciphering the analysis for the detection of the Australian antigen, an indicator of 0.5 IU / ml is taken as an acceptable limit. If the amount of antigen is below this indicator - the person is healthy, a positive result means that the concentration of HBsAg is higher than the allowable indicator.

Negative indicators do not always mean that a person is absolutely healthy, and there is no pathogenic virus in his blood. Values ​​below the acceptable limit of 0.5 IU / ml may also indicate that there was an infection, but the person is at the stage of recovery. There is also a possibility that there was an infection with two different groups of hepatitis - C and D (if hepatitis C is suspected, an HVC analysis is performed).

To be completely sure of the absence of a pathogenic virus, even with a negative result, it is necessary to take into account the absence or presence of symptoms of the disease and cases in which infection could occur. If a person has had unprotected intercourse and there are doubts about a partner, if a negative result is obtained, the test can be repeated after a while.

A negative result of this study for the Australian antigen does not exclude infection, but hepatitis B may have a weak replication, or the disease proceeds in a chronic form. In some cases, negative readings are a sign of hepatitis, which has a defective antigen.

A positive result, in most cases, indicates the presence of the Australian antigen in the human blood, but the error of the laboratory workers cannot be ruled out.

5 What does a positive result mean?

Positive blood tests are not always a sign of the presence of a pathogenic hepatitis virus in the body. There is no need to immediately panic, since the human factor of making mistakes is never excluded. If a positive result was obtained, doctors recommend repeating the test, but in a different laboratory. An incorrect result may be due to ignoring the requirements for preparing blood sampling if a person has eaten in the morning or is undergoing drug treatment, which he did not inform the laboratory assistant about.

Hepatitis B is not such a rare disease, so cases where a positive result indicates the presence of a pathogenic virus are more common than errors. The presence of the Australian antigen in the blood indicates infection with hepatitis, but a person who has a pathogenic virus may never get sick with this pathology, at the same time he is a carrier of a dangerous infection and should be aware of it. A positive result indicates the development of the disease in the body in an acute or chronic form.

If the Australian antigen was found in the human blood during the decoding of the test, it is necessary to undergo a medical examination. The initial stages of the disease do not require treatment until the virus begins to attack the liver. This is a precautionary measure, since not in all cases hepatitis provokes complications for the liver, and medications will only cause its intoxication. In acute pathology, the patient should be isolated in a hospital. People with a chronic and latent form of the disease need to be tested for HBsAg several times a year and examine the liver for the appearance of pathological processes in it.

6 Quick test

Patients who have been diagnosed with latent forms of hepatitis B, or if a person is undergoing treatment and it is necessary to regularly conduct tests to determine the concentration of the Australian antigen in the blood, you can use a special rapid test for home use, you can buy it at a pharmacy.

The express test is a qualitative diagnostic method, but its information content is not as accurate as the analysis carried out in a medical laboratory. The study requires a blood sample from a finger. Before taking biological material, the skin at the puncture site must be disinfected and dried.

The skin is pierced with a special lancet. To get the result of the examination, you will need a few drops of blood, which must be applied to the test strip. It is strictly forbidden to touch the test strip with your finger, otherwise, the information content of the test will be a big question. One minute after applying the blood, the test strip is placed in the reagent container.

How to decipher the result of a rapid test? If one band appears on the strip, the result is negative, with a positive analysis there will be 2 bands. This is not a method for diagnosing a disease and is used, in most cases, by patients who are undergoing hepatitis treatment and want to track the dynamics of recovery themselves.

7 If you need precision

There is always a risk of erroneous results in laboratory tests performed to detect Australian hepatitis in human blood. The most accurate analysis is the serological diagnostic method. This method allows you to detect the presence of pathogenic hepatitis virus in the early stages of the development of the disease - at 3-5 weeks.

In most cases, it lasts up to 3 months from the moment of infection. But cases when a person is a carrier of a virus, not a disease, are not so rare. The method of serological diagnostics detects anti-HBs antibodies. These enzymes are produced by the body during the recovery period, and their concentration in the blood increases as the hepatitis virus is destroyed. The presence of anti-HBs remains in the blood of a person who has had hepatitis and has been cured, forever. Thanks to these enzymes, re-infection with hepatitis B after complete recovery is impossible.

For a serological test, a venous blood sampling is performed. Preparation for analysis is the same as for many other tests - it is carried out only in the morning, on an empty stomach. A few days before the test, you must stop taking medications, fatty and peppery foods, and alcohol. It will take a day to decipher the analysis.

False-negative or false-positive results cannot be ruled out regardless of how the Australian antigen test is performed. Perhaps this is even when using the serological method. Such results are associated with a violation of the rules for preparing for the delivery of an analysis, an error in the work of a laboratory assistant or poor-quality equipment on which the analysis was performed.

Hepatitis B is an extremely dangerous disease that leads to severe liver complications. Not a single person is immune from infection, and given the long incubation period, the symptomatic picture appears at the time of the active development of the disease. To protect yourself, you must regularly undergo a medical examination and take laboratory tests.

The hepatitis B risk group includes not only medical workers, but also people traveling on vacation or on duty to eastern countries, where the level of hepatitis B is one of the highest in the world. Prior to travel, it is necessary to carry out appropriate vaccinations, during your stay in the country, follow preventive measures, and upon returning home, it is mandatory to take a blood test to detect HBsAg.