Mutant Viruses And Chronic Infection
Anti-HBe-positive patients in the reactivated phase of the disease are also referred to as the HBeAg-negative viremic group. Genomic analyses has revealed that such patients carry natural mutants of the virus that have either reduced levels or complete abrogation of HBeAg production. These variants are selected at the time of, or soon after, seroconversion, and become dominant during the reactivation phase. The most common precore mutation is the G1896A substitution, which creates a premature stop codon in the precursor protein from which HBeAg is elaborated. This mutation affects the stem of the encapsidation signal, but leads to stronger base pairing with the A1896 change in genotypes with a T at position 1858 of the precore region, such as B, C, D, and E. The double mutation affecting the core promoter region is thought to result in decreased transcription of the precore mRNA, with a knockon effect on HBeAg production, while pgRNA production remains the same or is even upregulated. It is now apparent that additional mutations in this region may contribute to this phenotype.
Geoffrey M. Dusheiko, in, 2003
Hepatitis B Surface Antigen Test
A hepatitis B surface antigen test shows if youre contagious. A positive result means you have hepatitis B and can spread the virus. A negative result means you dont currently have hepatitis B. This test doesnt distinguish between chronic and acute infection. This test is used together with other hepatitis B tests to determine the .
Results Of The Hbcab Test
There are two variations of antibodies. The IgM antibody is the largest antibody and the first produced in an infection. It shows that you may have a current, active infection. Sometimes it persists for years, but it usually drops to undetectable levels.
The HBcAb IgG variant is produced later in the course of the infection, and it’s likely that you will have a positive HBcAb IgG test the rest of your life.
The screening panel usually has a test that is for total HBcAb, which includes both IgM and IgG. The IgM test may be ordered to help determine if you have an acute infection.
A positive HBcAb test must be interpreted along with the results of the other tests. You may have an active or chronic infection, or you may be immune to hepatitis B due to past infection. Discuss the results with your healthcare provider. In any case, a positive HBcAb test means your blood or organs cannot be donated to a recipient.
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Hepatitis B Core Antibody Total Blood Test
A Hepatitis B Core Antibody Total Blood Test is used to find out if you are infected with the hepatitis B virus.
Also Known As: Anti-HBc Antibody to Hepatitis B Core Antigen HBcAb Total
Methodology: Immunochemiluminometric assay
Preparation: No fasting required. Stop biotin consumption at least 72 hours prior to the collection.
Test Results: 2-3 days. May take longer based on weather, holiday or lab delays.
Also Known As: Anti-HBc Antibody to Hepatitis B Core Antigen HBcAb Total
Methodology: Immunoassay
Preparation: No fasting required. Stop biotin consumption at least 72 hours prior to the collection.
Test Results: 2-3 days. May take longer based on weather, holiday or lab delays.
How To Get Tested
Hepatitis B testing is typically prescribed by a doctor and performed in a hospital, lab, or other medical setting. Taking a hepatitis B test requires a blood sample, which can be collected by a health care professional.
For laboratory-based testing, blood is drawn from a patients vein. After blood is collected, the sample is sent to a laboratory for analysis.
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Acute Hepatitis B Infection
High titers of immunoglobulin M anti-HBc, thought to be predominantly a thymus-independent response, appears early in the course of acute HBV infection, together with HBsAg and HBeAg . Anti-pre-S1 may also occur early in the course of infection. This is accompanied by a vigorous major histocompatibility complex class I restricted cytolytic T lymphocyte response against multiple epitopes throughout the structural and nonstructural proteins of the virus. The CTLs, by direct lysis of infected hepatocytes, are thought to be important in clearance of the virus. There is also some evidence for a role in viral elimination of the cytokines interferon γ and tumor necrosis factor α .
Figure 2. The natural history of acute HBV infection. HBsAg and HBeAg can be detected early in the serum, prior to the onset of clinical hepatitis. Antibody to pre-S1 can sometimes be detected during this early phase. AST (aspartate aminotransferaseis an indication of lysis of infected hepatocytes.
There is a strong MHC class II restricted T helper cell proliferative response to the nucelocapsid antigens, HBcAg and HBeAg, but not to the envelope proteins, during the early phase of acute hepatitis B. The association of recovery with the presence of the MHC class II locus DRB1*-1302 supports an important role for the CD4 response in recovery.
Louis M. Katz MD, Roger Y. Dodd PhD, in, 2013
Can I Take The Test At Home
Samples for hepatitis B testing can be collected at home. At-home hepatitis B testing requires a patient to collect a blood sample, typically from a fingerstick using a very small needle provided in the test kit. Once a blood sample is collected, it is prepared according to the instructions contained in the test kit and mailed to a laboratory for testing.
Because there are numerous types of tests for HBV, it is important to look closely at the specific components of any at-home test kit. Many at-home test kits only look for hepatitis B surface antigen .
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Clinical Information Discusses Physiology Pathophysiology And General Clinical Aspects As They Relate To A Laboratory Test
Hepatitis B e antigen is a small polypeptide that exists in a free form in the serum of individuals during the early phase of hepatitis B infection, soon after hepatitis B surface antigen becomes detectable. Serum levels of both HBeAg and HBsAg rise rapidly during the period of viral replication. The presence of HBeAg in serum correlates with hepatitis B virus infectivity, the number of infectious virions, and the presence of HBV core antigen in the infected hepatocytes.
During recovery from acute hepatitis B, HBeAg level declines and becomes undetectable in the serum, while hepatitis B e antibody appears and becomes detectable in the serum. Anti-HBe usually remains detectable for many years after recovery from acute HBV infection.
In HBV carriers and patients with chronic hepatitis B, positive HBeAg results usually indicate presence of active HBV replication and high infectivity. A negative HBeAg result indicates very minimal or no HBV replication. Positive anti-HBe results usually indicate inactivity of the virus and low infectivity. Positive anti-HBe results in the presence of detectable HBV DNA in serum also indicate active viral replication in these patients.
Hepatitis B Core Antigen And Hepatitis B Core Antibody
Hepatitis B core antigen cannot be detected in serum, but the antibody against it can. During acute infection, anti-HBc is predominantly of IgM class. IgM anti-HBc is an indicator of acute HBV infection and may be the only marker during the window period . It usually appears within 1 month of HBsAg detection and typically lasts for between 4 and 12 months. As acute infection recovers, IgM anti-HBc titers decrease and IgG anti-HBc titers increase. IgM anti-HBc can persist at low titers in patients with chronic HBV infection and these titers can increase during exacerbations of chronic hepatitis B.36 IgG anti-HBc is present along with anti-HBs in persons who have recovered from HBV infection and in association with HBsAg in those who are chronically infected. Anti-HBc may be present in isolation many years after recovery from acute hepatitis B when the anti-HBs titer has fallen to undetectable levels or in longstanding chronic HBV infection when HBsAg titers have decreased below the level of detection. In persons at high risk for HBV infection or in those from endemic countries, the presence of isolated anti-HBc is most often an indicator of low-level HBV infection. Persons with isolated anti-HBc may experience HBV reactivation when immunosuppressed.
Irena Bronstein, Corinne E.M. Olesen, in, 1995
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Taking A Hepatitis B Test
Testing for hepatitis B is performed on a sample of blood. A doctor, nurse, or other health care provider can obtain a blood sample using a small needle to draw blood from a vein.
At-home hepatitis B testing requires that users carefully follow instructions provided in the test kit to collect a small sample of blood, package the sample, and mail it to a lab for testing.
What Does Hepatitis B Core Antibody Positive Mean
Hepatitis B is an inflammation of the liver caused by a virus. Signs of hepatitis include tiredness or fatigue, fevers, loss of appetite, nausea, diarrhea, vomiting, headache, itchy skin, muscle soreness , jaundice , dark urine, and light stools.Here are some hepatitis B facts:
1. HBV infections will occur in one out of every 20 people at some time in the United States
2. Your risk of HBV is greater if you have sex with someone who has HBV.
3. Your risk is greater if you have a job that places you in contact with human blood.
4. Your risk is greater if you travel to areas where HBV is common.
Some people who donate blood get a letter from the blood bank saying that they are hepatitis B core antibody positive. Dont panic. This does not mean that you have hepatitis B, but you should get a more thorough screening. There are three blood tests that are used to diagnose hepatitis B: hepatitis B surface antigen, hepatitis B surface antibody, and hepatitis B core antibody positive. If your blood tests show that you are hepatitis B core body positive, it means that you either have a present infection or that you were infected in the past. There is a possibility of having a false hepatitis B core antibody positive. Blood banks only screen for hepatitis B core antibody positive and not for surface antigens or antibodies.
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Hbv Dna Hbv Genotype And Hbv Drug Resistance Assays
Specimen: Serum or plasma
Container: Red-top tube, yellow-top tube , gel-barrier tube, plasma preparation tube, or lavender tube
Collection method: Routine venipuncture
The specimen should be transfused to separate plasma/serum from cells within 6 hours and kept frozen when testing cannot be done promptly.
The tests use PCR amplification, DNA probe hybridization, and sequencing method.
Why It Is Done
Hepatitis B testing is done to:
- Find the type of infection and see if an infection has occurred recently or in the past.
- Screen people who have a higher chance of getting or spreading hepatitis B. This includes doctors, dentists, and nurses.
- Screen blood donors and donor organs to prevent the spread of hepatitis B.
- Find out if a person has antibodies after getting a hepatitis B vaccination. Having antibodies means the vaccine worked.
- Find out if hepatitis B is the cause of abnormal liver function tests.
- See how well treatment of chronic hepatitis B is working.
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Hepatitis B Antibody Reactive Means
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How Much Does The Test Cost
The cost of hepatitis B testing depends on the tests that are performed, where the test is conducted, and a patients health insurance coverage. When testing is ordered by a doctor, patients with health insurance may find it helpful to discuss the cost of testing with their health insurance company as they may be responsible for testing costs as well as other out-of-pocket costs such as copays and deductibles.
For patients without health insurance or for whom insurance doesnt cover the cost of testing, it may be helpful to discuss the cost of hepatitis B testing with a doctor or hospital administrator.
The cost of at-home hepatitis B testing starts around $45. At-home test kits may also test for additional types of viral hepatitis in the same sample. The cost of test panels that look for more than one type of viral hepatitis start around $80.
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The Fourth Or Reactivation Phase
The previous phase of HBeAg-negative/anti-HBe-positive inactive HBsAg carrier state is not synonymous with permanent termination of HBV replication and of HBV-induced chronic liver damage. Although the majority of patients may remain for life in an inactive HBsAg carrier state, and a number of them may also lose HBsAg and enjoy a complete recovery, others retain or redevelop over time significant HBV replication and progressive liver damage .
This state of HBV-induced liver damage has been first referred to as HBeAg-negative/anti-HBe-positive CHB, and similarly to HBeAg-positive CHB, it also represents an immune active phase in the natural course of chronic HBV infection. It is generally viewed as a fourth phase in the natural history of chronic HBV infection usually developing because of reactivation of HBV replication, though in some patients, it may immediately follow the second phase of HBeAg-positive CHB despite clearance and even seroconversion of HBeAg .
Stephen N.J. Korsman MMed FCPath, … Wolfgang Preiser MRCPath, in, 2012
Planning Therapy For The Patient
Overall it is possible to offer a sustained HBeAg/anti-HBe seroconversion rate of 3040% of immunocompetent adults with adult acquired disease. Treatment can be stopped 6 months after HBe clearance.
Many patients, however, have only minimal liver disease and the risks of therapy with side effects of drugs and emergence of resistance have to be weighed against the clinical benefit and the healthcare costs.
Studies such as the REVEAL study55,56 have been helpful in determining which patients are most likely to benefit from therapy and this is acknowledged in guidelines.
This study showed that a worse disease outcome is seen in those with higher levels of HBV replication. Guidelines generally recommend targeting therapy to those with active viral replication and evidence of progressive liver disease.57,58 The potential risks and benefits of therapy have to be carefully assessed for the individual patient and guidelines are being frequently updated59 with the development of new agents and the results of more long-term studies. Interferon is often recommended as a first-line therapy, particularly in those with a reasonable chance of response as it is a one-off therapy.
J Westin, in, 2005
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What Is Hepatitis B Surface Antibody
When you are exposed to hepatitis B, your body mounts an immune reaction against it as an invader. This happens whether you are exposed due to blood or sexual contact or if you are vaccinated with the hepatitis B vaccine.
The hepatitis B virus has proteins on its surface that cause your immune system to produce antibodies. With the vaccine, the sample contains the protein only and not the virus itself.
The first response your body will make when exposed to hepatitis B is to manufacture hepatitis B IgM antibodies. These early antibodies are produced to fight against several parts of the virus including its core. These antibodies are seen in the initial response, but they eventually fade away.
Your immune system then begins to produce IgG antibodies. It continues to produce these antibodies for the rest of your life. In this way, your immune system is always ready to attack hepatitis B virus when it is exposed to it.
Discusses Physiology Pathophysiology And General Clinical Aspects As They Relate To A Laboratory Test
Hepatitis B core antibodies appear shortly after the onset of symptoms of hepatitis B infection and soon after the appearance of hepatitis B surface antigen . Initially, anti-HBc Ab consist almost entirely of the IgM class, followed by appearance of anti-HBc IgG, for which there is no commercial diagnostic assay.
The anti-HBc total antibodies test, which detects both IgM and IgG antibodies, and the test for anti-HBc IgM antibodies may be the only markers of a recent hepatitis B infection detectable in the “window period.” The window period begins with the clearance of HBsAg and ends with the appearance of antibodies to hepatitis B surface antigen . Anti-HBc total Ab may be the only serologic marker remaining years after exposure to hepatitis B.
This assay is FDA-approved for in vitro diagnostic use and not for screening cell, tissue, and blood donors.
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Hepatitis B Core Ab Total Reactive
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Hepatitis B Core Antibody Igm Serum
Diagnosis of acute hepatitis B infection
Identifying acute hepatitis B virus infection in the serologic window period when hepatitis B surface antigen and antihepatitis B surface are negative
Differentiation between acute and chronic or past hepatitis B viral infections in the presence of positive anti-hepatitis B core
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Understanding Your Test Results
Understanding your hepatitis B blood tests can be confusing. It is important to talk to your health care provider so you understand your test results and your hepatitis B status. Are you infected? Protected? Or at risk? The Hepatitis B Panel of blood tests includes 3 tests and all three results must be known in order to confirm your status.
Below is a chart with the most common explanation of the test results, but unusual test results can occur. Please note that this chart is not intended as medical advice, so be sure to talk to your health care provider for a full explanation and obtain a printed copy of your test results. In some cases, a person could be referred to a liver specialist for further evaluation.
More Detailed Information About Hepatitis B Blood Tests
An acute hepatitis B infection follows a relatively long incubation period – from 60 to 150 days with an average of 90 days. It can take up to six months, however, for a person to get rid of the hepatitis B virus. And it can take up to six months for a hepatitis B blood test to show whether as person has recovered from an acute infection or has become chronically infected .
The following graphic from the U.S. Centers for Disease Control and Prevention represents the typical course of an acute hepatitis B infection from first exposure to recovery.
According to the CDC, a hepatitis B blood test result varies depending on whether the infection is a new acute infection or a chronic infection.