Detection of Hepatitis B with blood test

Hepatitis B

Table of contents

What is Hepatitis B?

Hepatitis B is a type of viral hepatitis, an inflammation of the liver that is transmitted through contact with the blood or body fluids of a person carrying the virus. The infectious cells can lead to chronic infections.

At the onset of the disease, the patient is seropositive for the e antigen (HBeAg). This indicates that the virus replicates intensively. During this phase the patient’s body fluids and blood are extremely contagious. While this is occurring, the body is generating antibodies against the surface antigen of the virus (HBsAg) and immunoglobulin M (IgM) against the core antigen (HBcAg).

Hepatitis B has different levels. If the patient’s own immune system is able to fight off the infection, we speak of acute hepatitis B. In this case, the individual should recover on his or her own within a maximum period of 6 months. Symptoms may last a few weeks.

If the disease cannot be fought by the organism and is dilated for a period longer than 6 months, we would be talking about a chronic infection. The fact that hepatitis B remains in the body is due to the persistence of HBsAg, regardless of whether HBeAg appears or not. A prolonged presence of HBsAg could mean chronic liver disease or liver cancer (hepatocellular carcinoma) in the future. When the disease is chronic, drugs should be used to treat it. 

It is very important to take a medical history of hepatitis B, because if the disease was contracted at some point in childhood, it is much more likely to be contracted again in adulthood.

Hepatitis B is currently incurable; there are only vaccines to prevent it. Chronic hepatitis B can be treated with antivirals to prevent the virus from replicating. However, the most important thing is to detect the disease early. If it is determined that a patient is suffering from acute hepatitis, he or she should be followed up so that it does not become chronic.

How is the Hepatitis B test performed?

Hepatitis B can be diagnosed by detection via chemiluminescence of HBV surface antigen (HBsAg) or Australia antigen. Unlike other viruses, hepatitis B can be diagnosed from the incubation period to the chronic stage. No prior preparation is needed to be able to perform the test.

Why get tested?

It is essential that a patient be tested for hepatitis B if he or she has symptoms of HBV or has been in contact with the blood or fluids of an HBV-infected person. It is also highly recommended if the patient has risk factors for contracting HBV. Some of them may be jaundice or high levels of transaminases in the blood. If you intend to conceive or if a woman is already pregnant, it would be very important to perform this test, as this disease is very contagious from mother to child at birth.

When should the test be performed?

One should wait 4 to 9 weeks if it is suspected that a person might have contracted the virus, since before this period hepatitis B might be undetectable. The sample needed would be venous blood.

What are the reference values for hepatitis B?

The reference values for a chemiluminescence assay for hepatitis B surface antigen testing are as follows:

Positive >1

Indeterminate 0.90 – 1.00

Negative <0.90

Can false positives occur?

Especially in pregnancy, the screening-based chemiluminescence technique can give false positives. In order to be sure whether or not it is a false positive, it is advisable to perform a neutralization test after the test.

Are there other screening tests?

In addition to the chemiluminescence method, there are other tests that can detect the presence of hepatitis B in the body. They are able to expand the information on the state of infection thanks to the levels of anti-Hbs antibodies, anti-HBc IgM, anti-HBc IgG, or HBeAg antigen. We can also know the effectiveness of the vaccine thanks to the presence of anti-HBs surface antibodies, in order to keep a history.


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