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  ความเข้าใจ / การแปลผล
  การตรวจ ไวรัสตับอักเสบ บี
  Understanding your   
  Hepatitis B Blood test 
  Results

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 Hepatitis B frequently 
   asked questions



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 Understanding your hepatitis B blood test results       
It is important to carefully discuss your test results  with your health care
provider. You may want to take this sheet with you to your appointment as a
reference guide. In addition, it is helpful if you request a written copy of your 
blood tests so that you can be sure you know your results.

Before explaining the tests, here are two basic medical terms:

  • Antigen - this is a substance that sets off an alarm in your body to 
    protect itself (e.g. hepatitis B virus)
  • Antibody - this is produced by the body to protect itself from an 
    antigen. Antibodies bind to and often inactivate antigens.

 

Common Blood Tests for Hepatitis B Infection

HBsAg (hepatitis B surface antigen) - This is 
the outer surface of the hepatitis B virus that 
triggers an antibody response. HBsAg 
"positive" or "reactive" means that the person 
is infected with HBV and can potentially pass it 
on to others who are in close daily contact.

HBsAb (hep B surface antibody) - The 
presence of antibodies indicates that a person 
has been exposed to HBV, but successfully 
cleared the virus from their body and is no longer contagious to others. The 
antibody protects the body from any future exposure to HBV infection - a 
person has been "naturally immunized". Antibodies are also produced from 
the HBV vaccine series.

Anti-HBc (antibody to hepatitis B core) - This test is used to identify a past or 
present HBV infection. It is produced during and after acute HBV infection. The 
core antigen is part of the hepatitis B virus and the antibody to the core antigen  
is usually present in chronic carriers. However, if it is present with a "positive" 
anti-HBs (protective antibodies), then it is associated with recovery from an 
infection and this person is not a carrier. The interpretation of this test depends 
on the first two test results.

Additional Blood Tests for Hepatitis B Carriers
E-Antigen - This is a viral protein that is 
secreted by HBV infected cells. Its 
presence indicates high levels of virus in 
the blood which increases a carrier's 
infectiousness to others who are in close 
contact. If this test is negative, but a person 
is known to be HBsAg positive, then it 
indicates low levels of virus in the blood, 
which decreases one's infectiousness. 
This test is often used to monitor the 
effectiveness of some HBV therapies, 
whose goal is to convert a carrier to 
"e-antigen negative".

E-Antibody - Carriers who stop producing e-antigen sometimes 
produce e-antibodies. The clinical signficance of this result is uncertain.

Liver Function Tests (or Liver Enzymes) - Includes blood tests that 
assess the general state of the liver and biliary system. When elevated 
above normal values, the ALT (alanine aminotransferase) and AST 
(aspartate aminotransferase) tests indicate damage to liver cells. The 
ALT and AST are enzymes that are located in liver cells and leak out into 
the bloodstream when liver cells are injured.

AFP (Alpha-FetoProtein) - This is a normal protein produced in the 
devloping fetus. Pregnant women will have elevated AFP's. Other adults, 
however, should not have much AFP in their blood. In a chronic carrier, 
high levels of AFP could indicate the possibility of liver cancer since this 
kind of tumor produces AFP.

Ferritin - Iron is stored in the liver in the form of Ferritin. Increased levels 
of Ferritin means there is a high iron storage. This could result from an 
increased iron intake in the diet (vitamin supplements, food cooked in iron 
pots, etc.). An elevation can also occur from a destruction of liver cells 
causing leakage of Ferritin. More research is needed to understand the 
relationship between elevated Ferritin and liver tumors.

Visit our Glossary for additional terms.

Interpretation of the Hepatitis B Blood Tests

Tests

Results

Interpretation

Recommendation

HBsAg

HBsAb (anti-HBs)

HBcAb (anti-HBc)

negative

negative

negative

Not immune - has not been infected, but is still at risk for possible future infection. Needs protection.

Get the vaccine.

HBsAg

HBsAb (anti-HBs)

HBcAb (anti-HBc)

negative

positive

negative or positive

Immune - surface antibodies present. You may have been already vaccinated. Or you have recovered from a prior hepatitis B infection. You cannot infect others.

The vaccine is not needed.

HBsAg

HBsAb (anti-HBs)

HBcAb (anti-HBc)

positive

negative

negative or positive

New infection or a Chronic Carrier - positive surface antigen, which means hepatitis B virus is present. You can spread the virus to others.

Find a knowledgeable doctor for further evaluation.

HBsAg

HBsAb (anti-HBs)

HBcAb (anti-HBc)

negative

negative

positive

*Unclear. Several different interpretations are possible. You may need to have these tests repeated. See below.

The vaccine may or may not be needed. Find a knowledgeable doctor for further evaluation.

*Positive Hepatitis B Core-Antibody Test Result (HBcAB+)

1. May be recovering from acute HBV infection
2. May be distantly immune and test not sensitive enough to detect  low 
    level of anti HBs in serum
3. May be susceptible with a false positive anti-HBc
4. May be undetectable level of HBsAg present in the serum and the 
    person is actually a carrier

Please Note: The interpretation of  each  individual's results should 
receive expert evaluation. Unusual results do occur and the above is 
actually an "average" representing the most likely interpretation. The 
chart above is provided as a guide for the general public; it is not intended 
as personal medical advice. All individuals are strongly encouraged to 
consult their own health care provider to evaluate their blood test results. 


What does the test result mean?
  • Hepatitis B surface antibody (anti-HBs): a positive result indicates immunity to hepatitis B from the vaccination or recovery from an infection.
  • Hepatitis B surface antigen (HBsAg): A negative result indicates that a person has recovered from acute hepatitis and has rid themselves of the virus. A positive (or reactive) result indicates an active infection but does not indicate whether the virus can be passed to others.
  • Hepatitis B e-antigen (HBeAg): A positive (or reactive) result indicates the presence of virus that can be passed to others. A negative result usually means the virus cannot be spread to others, except in parts of the world where infection with strains that cannot make this protein are common.
  • Anti-hepatitis B core antigen (anti-HBc): If it is present with a positive anti-HBs, it usually indicates recovery from an infection and the person is not a carrier. In acute infection, the first type of antibody to HBc to appear is an IgM antibody. Testing for this type of antibody can prove whether a person has recently been infected by HBV (where IgM anti-HBc would be positive) or for some time (where IgM anti-HBc would be negative).
  • HBV DNA: A positive (or reactive) result indicates the presence of virus that can be passed to others. A negative result usually means the virus cannot be spread to others, especially if tests that can pick up as few as 1,000 viruses (copies) in one mL of blood are used.

In most cases, test results are reported as numerical values rather than as "high" or "low", "positive" or "negative", or "normal". In these instances, it is necessary to know the reference range for the particular test. However, reference ranges may vary by the patient's age, sex, as well as the instrumentation or kit used to perform the test. To learn more about reference ranges, please see the article, Reference Ranges and What They Mean. To learn the reference range for your test, consult your doctor or laboratorian.

 

 Hepatitis B frequently asked questions

What should I do if my test result is positive?

If your test result is positive, you will see a red dot in the middle of the test cartridge. 
A positive or unclear (faint dot) test result should be retested to confirm the first result. A repeatedly positive test result is reason to assume the presence of hepatitis B surface antigens. 
Never interpret a positive test result as absolute proof of a hepatitis B infection. All repeatedly positive or unclear test results should be reconfirmed by other methods.
If the test result is positive, we advise you to consult a doctor. If necessary, change your lifestyle and habits to exclude the possibility of infecting other people, until you are certain you are not infected with hepatitis B.

Does a negative test result mean that I have no hepatitis B infection?

If the result is negative, you can assume the absence of hepatitis B antigens in the blood sample. Also in this respect, our test is highly accurate (more than 99,5 %). You may conclude that you are not infected. However, a negative test result does not entirely exclude the exposure to, or infection with hepatitis B. 
Generally, it is not considered necessary to reconfirm a negative test result, so you do not have to do a second, confirmatory, test.

Who should test for hepatitis B?

The hepatitis B virus is present in blood, sperm and body fluids. It is possible to be infected and show no symptoms while infecting others. Hepatitis B is 80 to 100 times as infectious as HIV. The most common causes of infection are :

  • unprotected sexual contact with an infected person
  • multiple use of needles by intravenous drug users 
  • use of unsafe blood products or blood transfusions using unsafe blood 
  • infection of a newborn baby by an infected mother 

If you suspect you have been at risk, or belong to high risk groups and you have not been vaccinated yet, it is wise to test for hepatitis B.
Groups with increased risks for hepatitis B infection : 

  • people originating from the Mediterranean countries, Eastern Europe, Africa, Asia and Surinam. 
  • healthcare workers that get in touch with blood 
  • chronic hemodialysis patients 
  • children of infected mothers 
  • people with multiple sexual partners 
  • shared users of needles, razor blades and toothbrushes 
  • intravenous drug users 
  • people with ear and body piercing and tattoos 
  • recipients of blood transfusions before 1975 

What is the difference between a carrier of hepatitis B and an (acute) infection with hepatitis B?

Usually, there is an incubation period of approximately 90 days from the moment of infection until the first symptoms show. After this period, the following symptoms may occur : 

  • loss of appetite 
  • nausea and vomiting 
  • fever 
  • general achiness 
  • abdominal pain 
  • fatigue 
  • dark brown urine 
  • yellowish skin and eyes (jaundice) 

Alternatively, there may be no symptoms at all. The disease may last several weeks to months. During and after this time, patients will be fatigued.
In most cases, the virus will disappear within half a year after which the patient will have formed antigens and is subsequently immune for new hepatitis B infections nor can they infect others anymore.

It is also possible that the hepatitis B virus is only partially eradicated by the patients immune system. Little or no symptoms show in these cases. These patients become carriers. The virus is still present in the body and the patients can infect others. Being a carrier usually has little consequences for the patient, however, after many years of being a carrier, there is an increased risk for cancer of the liver and at any time the virus may become active again. 
A relatively small percentage of patients experience chronic hepatitis and experience no decrease in virus activity. These patients continue to show the above symptoms and remain infectious to others.
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