BBV Testing

Hepatitis B core antibodies (Anti-HBc) are a type of antibody that the body produces in response to a part of the hepatitis B virus called the core antigen.

The presence of these antibodies can indicate a past or current hepatitis B virus (HBV) infection. They typically appear shortly after the onset of symptoms or infection, and usually remain in the bloodstream for life, even after the disease has resolved.

There are two types of Anti-HBc antibodies: IgM and IgG. IgM is the first antibody to appear after infection and it usually indicates a new or acute infection. IgG replaces IgM over time and typically signifies a past infection or a chronic (ongoing) infection.

The Anti-HBc antibodies are an important biomarker in diagnosing and understanding the timeline of a hepatitis B infection. However, they cannot differentiate between an active or previous infection on their own, and additional testing (e.g., testing for the presence of the Hepatitis B surface antigen, or HBsAg) is needed for a comprehensive picture of a person's hepatitis B status.

Hepatitis B surface antigen (HBsAg) is a protein on the surface of the Hepatitis B virus. It's present in the blood of someone who is infected.

When a person is infected with Hepatitis B, the HBsAg is the first marker that appears in the blood, even before symptoms start to appear. Therefore, a test that detects the presence of HBsAg is used to diagnose current Hepatitis B infections.

Typically, if the HBsAg remains positive for more than six months, it signifies a chronic (or long-term) Hepatitis B infection. If it becomes negative within six months, it means the person's immune system has successfully fought off the acute infection.

Importantly, the presence of HBsAg in the blood also signifies that the person is infectious and can pass on the virus to others. This is especially significant in the context of blood donation, needle sharing, sexual contact, and mother-to-child transmission.

While a positive HBsAg test indicates a current infection, additional testing is usually needed to determine whether the infection is acute or chronic, and to guide treatment decisions.

Remember that testing for HBsAg is crucial for early detection and management of Hepatitis B infections, helping to prevent the long-term consequences of chronic Hepatitis B, such as liver cirrhosis and liver cancer.

HIV, or Human Immunodeficiency Virus, is a virus that attacks cells that help the body fight infection, making a person more vulnerable to other infections and diseases. If left untreated, HIV can lead to the disease AIDS (Acquired Immunodeficiency Syndrome).

In the context of biomarker testing, the two most common biomarkers for HIV are:

HIV Antibodies: These are proteins produced by the immune system to fight HIV. The presence of HIV antibodies typically indicates that a person has been infected with HIV.

HIV Antigens: These are proteins produced by the HIV virus itself. The most commonly tested HIV antigen is p24, which can be detected in the blood within 2-4 weeks after HIV infection.

In most modern HIV tests, both antibodies and antigens are tested simultaneously in a combination (or "4th generation") test. This allows for earlier and more accurate detection of HIV than testing for antibodies alone. A positive result usually requires a follow-up test to confirm the diagnosis.

Here's a basic outline of how these tests work:

A sample of blood is collected.

The sample is examined for the presence of HIV antibodies and/or antigens.

If either HIV antibodies or antigens are detected, the test is considered positive, indicating that HIV infection may be present.

A positive result is usually confirmed with a follow-up test, such as an HIV RNA test, which can detect the genetic material of the virus.

It's important to note that it can take several weeks for the body to produce enough antibodies and antigens to be detectable by tests. This period, known as the "window period," varies from person to person but is typically around three weeks.