The HBsAg blood test is used to screen, detect, and diagnose hepatitis B [HBV] infections. It can discover acute infections even before the bothersome signs and symptoms of HBV make themselves down. It is treated as the primary method of determining if someone is in the carrier state of this viral infection.
It can be used in a wide variety of ways, including the screening of blood donations, detecting previous exposure, or to monitor an ongoing chronic HBV infection.
Some medical providers may use a series of HBV testing, including antibody testing, as part of an overall panel to determine the health status of the patient. The HBsAg blood test is not generally ordered as a follow-up test, but as a first-test option to detect the virus in the first place.
When to Speak to a Doctor About the HBsAg Blood Test
Hepatitis B may cause a series of bothersome signs and symptoms when an infection becomes active. Common symptoms include a fever, ongoing fatigue, a loss of appetite, nausea, vomiting, and abdominal pain.
Because this virus affects the liver, there may also be organ-specific symptoms present. This may include dark urine, clay-colored stools, yellowing of the skin or the whites of the eyes, and joint pain.
Mild symptoms may cause virus levels to be too low for the HBsAg blood test to detect, creating a false negative. For a patient suffering from these signs and symptoms, an ALT or AST blood test [or both] may be ordered since influenza and other viral infections can cause similar issues.
Certain Groups of People Should Be Tested
In addition to testing because of bothersome signs and symptoms, there are certain groups of people that the CDC in the United States recommends be regularly tested for HBV. This includes people who are public safety workers, those in the healthcare industry, and men who have intimate relationships with other men.
Certain medical conditions which require a suppression of the immune system should also be regularly tested for HBV. This is especially true for organ transplant recipients.
Those infected with HIV, have elevated liver enzyme levels with no known cause, or have a family history in Asia or Africa are also recommended to receive regular HBsAg blood testing.
Ongoing monitoring may require testing every 6-12 months.
What Do My Test Results Mean?
When the HBsAg blood test comes back as positive, then this generally means that there is an acute or active infection of HBV. It may also mean that there is a chronic HBV infection, but one that is at a low risk of liver damage. The final diagnosis depends on whether other HBV tests come back as positive or negative.
It is possible for a HBsAg blood test to come back as negative while an HBV infection is present. This occurs most often when the antibody tests for hepatitis B come back as positive, but the HBsAg blood test comes back as negative. In some areas of the world, HBV strains do not make certain antigens, so the results may be different.
Here’s What You Need to Know
Even if there are no bothersome signs and symptoms, HBV is able to damage your liver and spread the infection to other people. You may wish to get tested if you suspect an exposure or belong to a high-risk group to protect your health.
All blood banks use the HBsAg blood test to screen donated blood. Any donor that comes back with a positive test is notified of their results. It is recommended that anyone who receives a positive notification after a blood donation should contact their preferred medical provider for follow-up testing.
It is possible to avoid an HBV infection with a shot of immune globulin within 24 hours of a known transmission.
Specific strains of HBV can also be detected to determine if it is causing the infection. It is still in the research stage, but may be available as an option for certain patients.
Hepatitis D [HPD] is another virus that can damage the liver, but will only do so if HBV is present. It is possible to be infected with both hepatitis viruses at the same time.
The HBsAg blood test is an effective tool to help determine if donated blood or bothersome signs and symptoms involve HBV. Treating hepatitis B involves antiviral medications to slow its damaging effects. In severe cases, a liver transplant may be required. Use this guide to discuss any concerns you may have about your health with your preferred medical provider as only a doctor can properly diagnose this issue.