Hepatitis B is an extremely dangerous disease that affects the liver cells and sooner or later leads to the destruction of the organ. For the purpose of timely diagnosis of pathology, doctors prescribe an analysis of Hbs. This is a laboratory test that detects both antigens and antibodies produced by the body.
HbsAg and anti-Hbs: concept
Hepatitis B is caused by a virus. It consists of a specific set of proteins that determine the properties of a pathogenic microorganism. Those that are on the surface are called antigens. It is they that the immune system can recognize and subsequently produce antibodies whose task is to destroy the virus.
Surface antigen and is indicated in the conclusions of laboratories as Hbs Ag. This indicator is a very reliable marker of hepatitis B. However, this analysis is not the only one used to make an accurate diagnosis.
Some time after the penetration of the disease-causing agent into the body, the immune system starts the process of producing antibodies. In this case, in conclusion, expertslaboratories make a note “anti-Hbs positive”. At the same time, the doctor can determine the stage of hepatitis B by the concentration of antibodies in the blood. As a rule, the pathogen is detected in the liquid connective tissue 3 months after infection. However, medicine knows cases when a person has been a carrier of the virus all his life.
If the outcome of the disease is recovery or the pathology has become chronic, antigens in the blood are not detected. As a rule, this occurs 3-4 months after the development of the pathological process. Antibodies, on the other hand, appear immediately after infection, while their concentration only increases over time. They can even appear throughout life. Due to this, the body becomes immune to the re-penetration of the pathogen into its tissues.
Indications
It is important to understand that a blood test for Hbs is a specific study. It is prescribed only if the doctor has suspicions about the progression of hepatitis B in the patient's body.
Indications for Hbs analysis:
- Frequent headache episodes.
- Gradual deterioration of well-being.
- Disturbance of appetite up to its complete loss.
- Weakness, lethargy.
- Pain in muscles and joints.
- Signs of respiratory illness.
- Changing the color of urine. Urine in appearance is associated with dark beers.
- Yellowing of the oral mucosa and sclera. Skin acquires the same shadecover, it is most noticeable on the palms.
In addition, you need to know that a blood test for Hbs is a study that is mandatory for children whose mother suffers from hepatitis B. This is due to the fact that the virus is easily transmitted transplacental. In addition, all sexually promiscuous people, as well as people in whose family at least one member has been diagnosed with hepatitis B, are recommended to donate blood for an Hbs test.
Preparation
To get the most reliable result, you must follow certain rules. When prescribing, the doctor without fail tells what the Hbs Ag and anti-Hbs analysis is, how to prepare for it and how many days to wait for the results.
Rules of conduct before donating biological material:
- Blood is taken on an empty stomach. The last meal should take place 8-10 hours before. At the same time, it is recommended to give preference to easily digestible dishes. You can drink only pure non-carbonated water. Liquids containing even a minimal amount of sugar are prohibited. This is due to the fact that the use of glucose can significantly distort the results of the Hbs analysis.
- Immediately before donating the biomaterial, it is not recommended to brush your teeth. This is because most pastes contain sugar.
- Fatty meals should be excluded from the menu the day before the study. Even the use of butter often leads to the impossibility of conducting an Hbs analysis. What should bediet? The menu should contain vegetables and fruits (except those that are yellow and orange), lean meats or fish, cereals from all kinds of cereals.
- For 2 days you must stop drinking alcohol-containing drinks.
- Smoking is prohibited 1 hour before the blood donation procedure. This is due to the fact that tobacco has a negative effect on homeostasis.
- It is advisable to stop taking all medications 2 weeks before the study. If this is not possible for he alth reasons, it is necessary to inform the doctor about this.
- The day before blood sampling, it is necessary to abandon high-intensity physical activity.
In addition, the psycho-emotional state of a person can also affect the final result. In this regard, it is recommended to sit quietly and think about something good 15 minutes before donating blood.
Laboratory diagnostics
Research is qualitative. In other words, the result can be positive or negative.
The biological material is venous blood. The algorithm for collecting it is as follows:
- A nurse applies a tourniquet to her forearm (just above the elbow).
- The next step is to treat the skin at the intended injection site with an antiseptic.
- A nurse inserts a needle into a vein in the crook of the elbow and fills a test tube with blood. If the vessel is not available for palpation, another one is selected.
Immediately after collection of biological materialsent to the laboratory. If the Hbs analysis is negative, additional diagnostic measures are not required. If it is positive, quantitative tests may be ordered by the doctor.
Express diagnostics at home
Currently, it is possible to independently test Hbs for hepatitis B. To do this, it is enough to purchase a kit for express diagnostics at a pharmacy. No special equipment or reagents are required to carry out a qualitative study (but not a quantitative one).
Algorithm for express diagnostics:
- Treat any finger with an antiseptic solution.
- Puncture the skin with the included scarifier.
- Squeeze 3 drops of blood onto the test strip. In this case, it is desirable that the finger does not touch it.
- Wait 1 minute.
- After the specified time, add 3 drops of buffer solution to the test strip. The latter is also included in the set.
- Review the result after 10-15 minutes.
If you receive a doubtful or positive result, you must contact a medical institution and re-donate blood for analysis.
Methods for the study of biomaterial
Currently, there are already 3 generations of methods for the serological diagnosis of hepatitis B. They are presented in the table below.
| Generation | Methods |
| I | RPG (gel precipitation reaction) |
| II | VIEF (counterimmunoelectrophoresis), RSK (complement fixation reaction), RLA (latex agglutination reaction), MFA (fluorescent antibody method), IEM (immunoelectron microscopy). |
| III | RNHA (reverse passive hemagglutination test, RIA (radioimmunoassay), ELISA (enzymatic immunoassay). |
The most informative today are RIA and ELISA. This is due to the fact that during the study it is possible to identify immunoglobulins of classes M and G separately. This allows you to evaluate the dynamics of the pathological process.
The latest diagnostic method is PCR (polymerase chain reaction). This method is not only qualitative, but also quantitative. In addition, PCR research can be carried out even at the initial stage of pathology development.
Interpretation of results
Deciphering the analysis of Hbs should be handled by an infectious disease specialist or a hepatologist. In most cases, self-interpretation leads to false conclusions. This is due to the fact that during decoding it is necessary to take into account the value of not only Hbs Ag, but also other markers of hepatitis B, including the presence of antibodies.
As a rule, several indicators are indicated in the conclusion of the laboratory. Their comparison and allows you to make an accurate diagnosis. Value options and their interpretation are shown in the table below.
| Hbs Ag antigen | HbeAg antigen | HbsIg antibodies | HbcIgG antibodies | HbcIgM antibodies | Interpretation |
| + | + | - | - | + | Hepatitis B confirmed, the disease is in the acute phase. |
| + | +/- | - | + | - | Pathology has a chronic form. |
| + | - | - | - | - | A person is a carrier of the hepatitis B virus. |
| - | - | + | + | - | The patient has already had the disease in the past. |
| - | - | - | - | - | The presence of pathology is excluded. In addition, the person has never had hepatitis B in the past. |
When a doubtful or positive result is obtained, the doctor prescribes additional studies. Quantitative diagnostic methods allow you to determine the exact concentration of antibodies / antigens in the fluid connective tissue.
The result is positive: what to do next
In this case, it is customary to talk about the presence of hepatitis B in the patient's body. In this case, most often the disease is in the acute phase. As mentioned above, if the result is positive, further research is needed. When confirming the presence of an ailment, the Hbs analysis must be taken regularly. This allows the doctor to track the slightest changes in the body in a timely manner.
Based on the results of the diagnosis, the specialist draws up the most effective treatment regimen. As a rule, it includes the following items:
- Bed rest.
- Restriction of physical activity.
- Diet.
- Taking or administering medications (antiviral drugs, immunomodulators, detoxification solutions).
According to the current legislation of the Russian Federation, information about persons diagnosed with hepatitis B is transferred to the Department for Recording and Registration of Infectious Pathologies of the State Sanitary and Epidemiological Supervision.
You can donate blood for analysis anonymously. But in this case, the information is not transmitted to the relevant authority and, as a result, a person, upon receiving a positive result, cannot be hospitalized and receive medical assistance.
Where to return
Sampling of biological material for research is carried out in any independent laboratory or private medical institution. With regards to how much a blood test for Hbs is done. The term directly depends on the chosen diagnostic method. Typically, the wait is a minimum of 1 and a maximum of 3 business days.
Cost
It is important to know that you have to pay for Hbs Ag and anti-Hbs tests. Studies, even if you have a medical insurance policy, are not free of charge. The cost of one analysis is approximately 250 rubles.
In closing
Hepatitis B is a serious pathology, ignoring which leads to irreversible consequences. For timely detection of the disease, you can donate blood for analysis. Clinically significant are indicators of Hbs Ag and anti-Hbs. In the first case, we are talking about an antigen - a surface protein. It is for this substance andthe body's defenses react. The immune system begins to produce antibodies, the task of which is to destroy the pathogen. If you test positive for hepatitis B, you need to be treated. At the same time, blood must be donated regularly.
