Hepatitis B Virus Antibodies

Hepatitis B is a liver infection caused by the hepatitis B virus (HBV). It is one of several various causes of hepatitis, a condition characterized by inflammation and enlargement of the liver. Other causes of hepatitis include, for example, certain drugs, inherited disorders, and autoimmune diseases. HBV is one of five "hepatitis viruses" known to cause disease in humans . The other four are A, C, D, and E.

The course of HBV infections can vary from a mild form (acute) that lasts only a few weeks to a more serious, chronic form lasting years. Sometimes chronic HBV leads to serious complications such as cirrhosis or liver cancer.

HBV is spread through contact with blood or other body fluids from an infected person. Exposure can occur, for example, through sharing of needles for IV drug use or through unprotected sex. People who live in or travel to areas of the world where hepatitis B cases are high are at a greater risk. Mothers can pass the infection to their babies, usually during or after birth. The virus, however, is not spread through food or water, casual contact such as holding hands, or coughing or sneezing.

Some of the various stages or forms of hepatitis B include:

• Acute infection
  • People recently infected with HBV with a positive screening test. Some people have typical signs and symptoms including high temperature tiredness, pain in their right side and jaundice, but some people do not feel ill at all
• Chronic infection
  • People who are known to have been infected for more than 6 months with the virus detected by laboratory tests accompanied by inflammation of the liver
• Carrier (inactive) state
  • persistent infection but no signs of liver inflammation. A carrier may appear to be in good health but they still have the virus and can potentially infect others
• "Cleared" infection
  • no longer any evidence of infection; viral antigen and DNA tests are negative and no signs or symptoms of liver inflammation (although, in many cases, the virus is present in an inactive state in the liver)

There are several different tests that can be used to detect current or previous HBV infection. Some of the tests detect antibodies produced in response to exposure to the HBV; some detect viral antigens (part of the virus itself) while others detect viral DNA. They can be used to screen for infection in the absence of symptoms, to determine whether infection is acute or chronic, or to monitor a chronic infection.

 What does the test result mean?

Hepatitis B results are often requested in combination with tests for other viruses and other markers of disease, depending on the reason for testing. The results therefore will be evaluated together. Not everyone will need to have all the tests described here, so it is helpful to know which tests your doctor is requesting for you and why.

The table below summarises some of the results and what they mean. It is not fully comprehensive but covers the majority of common results.

Hep B surface antigen (HBsAg)	Hep B surface antibody (Anti-HBs)	Hep B core antibody (Anti-HBc IgM)	Hep B core antibody Total (Anti-HBc IgG+IgM)	Hep B e antigen (HBeAg)* see note below	Hep B e antibody (Anti-HBe)	Interpretation / Stage of Infection
Negative	Negative		Negative			No active or prior infection; not immune - may be good candidate for vaccine
Negative	Negative/low positive	Positive	Positive	Negative	Positive	Acute infection, now resolving
Negative	Positive	Negative	Positive	Negative*	Positive	Infection resolved: immunity due to natural infection
Negative	Positive		Negative			Immunity due to vaccination
Positive	Negative	Negative	Negative	Positive	Negative	Early acute infection
Positive	Negative	Positive or Negative	Positive or Negative	Positive	Negative	Acute infection – usually with symptoms: contagious
Positive	Negative	Positive	Positive	Negative*	Positive	Late in acute infection (seroconversion)
Negative	Negative	Positive	Positive	Negative*	Positive	Acute infection is resolving (convalescent)
Positive	Negative	Negative	Positive	Negative*	Positive	Chronic infection but low risk of liver damage – carrier state
Positive	Negative	Negative	Positive	Positive	Negative	Indicate active chronic infection – liver damage possible

 

HIV Antibody and HIV Antigen

Human immunodeficiency virus (HIV) infects the cells of a person’s immune system and is the cause of AIDS (acquired immunodeficiency syndrome).

When a person becomes infected with HIV, through exposure to the blood or body fluids of an infected individual, the virus begins to reproduce very rapidly. So, during the first few weeks of infection, the amount of virus (viral load) in the blood can be quite high.

The immune system responds by producing antibodies directed against the virus and these begin to be detected in the blood around 3-4 weeks after exposure to the virus. As the level of HIV antibody increases, the viral load in the blood decreases.

This early HIV infection may cause no symptoms or sometimes a flu-like or glandular fever-type illness. The only way to determine whether a person has been infected is through HIV testing. Modern HIV screening tests detect HIV antigens (parts of the virus itself, usually a protein called the p24 antigen) and/or antibodies produced in response to an HIV infection.

Two main test types are available for HIV screening:

• Combination HIV antibody and HIV antigen test— this is the recommended screening test for HIV and is available only as a blood test. By detecting both antibody and antigen, the combination test increases the likelihood that an infection is detected soon after exposure. These tests can detect HIV infections in most people by 2-6 weeks after exposure.
• HIV antibody testing— This test takes a little longer to become positive after an exposure but can be carried out on blood or oral fluid. HIV antibody tests can detect infections in most people 3-12 weeks after exposure.

Syphilis Test

The test is looking for evidence of Treponema pallidum, the bacterium that causes syphilis. Syphilis is a sexually transmitted disease. It is easily treatable but can cause severe health problems if left untreated.

The evidence of the presence of bacteria are:

Antibody
If syphilis producing bacteria enters your body then the body’s defence system (immune system) would start producing proteins against the invading bacteria to try to fight the infection. These proteins are called antibodies. In laboratories these antibodies, which are produced in response to syphilis infection can be identified and measured by tests called serological tests. Doctors can interpret this test result to find out if you are infected and if infected, how far the infection might have progressed. Doctors might need to repeat the test to confirm the diagnosis and interpret the result better.

Bacteria itself
If you have a sore, a swab or scrape may be collected to look for the bacteria under the microscope. It is called dark ground microscopy. This test is infrequently done now as it needs a lot of expertise and antibody testing is easier to do, quicker and reliable.

Bacterial genetic material
This test is called PCR (polymerase chain reaction). It looks for Treponema pallidum genetic material in a sample directly taken from the sore/ulcer.

Cytomegalovirus (CMV)

Cytomegalovirus (CMV) testing is requested to determine whether someone is currently, or has recently been, infected with CMV. It may also sometimes be used to determine whether someone has ever been exposed to CMV. Testing for CMV involves either a measurement of CMV antibodies (immune proteins created in response to CMV exposure) or by the detection of the virus itself. The virus is detected during an active infection by detecting the genetic material of the virus (its DNA).

In the United Kingdom, as many as 50% to 85% of adults have been infected with CMV. Most people are infected as children or young adults and do not experience any significant symptoms or health problems, but the most common symptoms are fever, tiredness and jaundice. CMV is found in many body fluids during an active infection, including saliva, urine, blood, breast milk, semen, cervical secretions, and cerebrospinal fluid. It is easily transmitted to others through sexual contact and sharing saliva or by contact with infected objects, such as nappies or toys. After the initial “primary” infection has resolved, CMV becomes dormant or latent - like other members of the herpes family. Cytomegalovirus remains in a patient for the rest of their life without causing any symptoms, unless the virus reactivates when a patient’s immune system is compromised.

CMV can cause problems in three areas:

• In young adults, the initial primary CMV infection may cause an illness characterised by fever, tiredness or jaundice; it usually resolves within a few weeks but can cause prolonged illness with fever and sweating.
• In infants, primary CMV infection may cause serious physical and developmental problems when women are first infected during pregnancy and then pass the infection to infants across the placental barrier. Most foetuses (about 90%) that are infected appear perfectly normal at birth but may develop hearing or vision problems, pneumonia, seizures, and/or delayed mental development a few months later. A few babies may be stillborn, while others may have symptoms at birth such as jaundice, anaemia, an enlarged spleen or liver, and a small head. Some of these signs and symptoms will resolve with time, but others may persist.
• In those with compromised immune systems, CMV may cause serious illness and death. This includes those with HIV/AIDS, those who have had organ or bone marrow transplants, and those undergoing chemotherapy treatment for cancer. Patients with compromised immune systems who become infected for the first time may experience more severe symptoms, and the CMV infection may remain active. Those who have been exposed to CMV previously may reactivate their infection. This may affect their eyes (causing inflammation of the retina, which can lead to blindness), gastrointestinal tract (causing bloody diarrhoea and abdominal pain), lungs (causing pneumonia with a non-productive cough and shortness of breath), and brain (causing encephalitis). There can also be spleen and liver involvement, and those who have had organ or bone marrow transplants may experience some degree of rejection. Active CMV also further depresses the immune system, allowing other secondary infections, such as fungal infections, to occur.