HBsAg Test (Hepatitis B Surface Antigen)

Serologic testing for HBsAg is a primary screening test and patient diagnosis helps in treatment of HBV with antiviral agents. An early detection and treatment may prevent progression to hepatocellular carcinoma. Once diagnosed patient can be educated on prevention of ongoing HBV transmission, vaccination, and life-style modification

An HBsAg Screening gets done to:

• Diagnose a suspected case of Hepatitis B Virus infection
• Monitor the condition of infected patients
• Check whether the infection gets resolved or the patient is now a chronic carrier of the Hepatitis B Virus.
• Predicts the clinical outcome of the disease
• Check for acute or chronic Hepatitis B Virus infection.
• Check if the patient needs post-test counselling.
• Check for the presence of Hepatitis B Surface Antigen in the patient's bloodstream.

Hbsag test measures hepatitis b surface antigen in the blood of the patient. This antigen is produced throughout the active viral replication

Hbsag test requires a blood sample. A tourniquet (elastic) band is placed tightly on the upper arm. The patient is then asked to make a fist. This helps in the build-up of blood filling the veins. The skin is disinfected before needle insertion and the blood sample is collected in vacutainer

An individual positive for HBsAg is considered to be infected results should be interpreted in light of other serological tests. To avoid false positive a HBs Ag- conformation is advisable.
A negative test may result if patient is in the 'window period' or early on in the infection; in such a case Anti HBc IgM or HBV DNA detection may help diagnose the condition.
Persistence of HBsAg is associated with chronic infection. Presence longer than 6 months after initial exposure indicates chronic infection.

Other tests along with HBsAg Screening include the anti-HBc IgG test (Total Hepatitis B core antibody test) and the HBV-DNA test.

anti-HBc IgG test: Antibodies appear at the onset of symptoms in the case of acute Hepatitis B and stay for life.

HBV-DNA test: This test measures the viral load of HBV in the bloodstream.

No preparation for the HBsAg Screening. Usually detectable after 30 days.

A healthcare provider will take your blood sample. An elastic band will get tightly tied to the upper arm. Your skin will get disinfected with cotton soaked in alcohol. The healthcare provider inserts the needle into your vein just above your elbow to collect your blood. The blood will then get poured into a serum separator tube. You may feel a prick when the needle enters and exits your vein. The healthcare provider then puts clean cotton over the punctured area.

HBsAg Screening gets usually measured in milli-international units per litre.

Negative: Less than 5.00 mIU/L

Indeterminate: More than or equal to 5.00 mIU/L and Less than 12.0 mIU/L

Positive: More than 12.0 mIU/L

Warning signs of Hepatitis virus infection are as follows -

• Easy bleeding
• Easy bruising
• Fatigue
• Poor appetite
• Itchy skin
• Yellow colouration of eyes and skin
• Fluid in the abdomen (a condition called ascites)
• Dark urine

People with the following lifestyle pose a risk of HBV -

• Having sex with a person infected with HBV priorly
• Men having sex with other men
• Living with someone who has the HBV infection
• A baby whose mother has the HBV
• Sharing needles for intravenous purposes
• Working in a healthcare environment where exposure to HBV is common
• Getting organ transplant
• Getting blood transfusion
• People with a prior HBV infection

Hepatitis B Blood Test

Hepatitis B Surface Antigen (HBsAg) Screen

Hepatitis B Serological Test

Screening for Viral Hepatitis

HBsAg Screening (Rapid) Test

HBV HBsAg Screening

HBsAg Rapid Test

HBsAg Test

Hepatitis B Antigen

Screening for Hepatitis B Virus Infection

A positive HBsAg test report indicates an active hepatitis B infection, and the person can transmit the virus to others. A negative result suggests no active infection.

If the HBsAg test is positive, further testing is needed to determine if it is an acute or chronic infection. The individual should be linked to hepatitis B care for appropriate management and treatment.

The benefits include early detection of hepatitis B, prevention of transmission, timely treatment initiation, reduction in liver disease-related morbidity and mortality, and cost-effectiveness in high-risk populations.

Pregnant individuals should undergo HBsAg screening, preferably in the first trimester, to prevent mother-to-child transmission. Infants born to HBsAg-positive mothers need testing and may require prophylaxis.

The value "150" in HBsAg testing typically refers to the signal-to-cutoff ratio or an index value indicating the strength of antigen presence. However, this is not a standard unit and can vary by laboratory.

The HBsAg test is highly accurate, with sensitivity and specificity over 98%, when performed using FDA-licensed or approved serologic assays according to the manufacturer's recommendations.

The HBsAg test is used to diagnose acute and chronic hepatitis B infections. It can also help diagnose related conditions such as cirrhosis and liver cancer through follow-up testing and clinical evaluation.

Certain medications, such as immunosuppressive therapy, can affect the interpretation of HBsAg test results, especially in terms of reactivation risk. However, the test itself is not directly affected by most medications.

No, fasting is not required before taking the HBsAg test. However, it is essential to follow any specific instructions provided by your healthcare provider or diagnostic center.

False positives can occur transiently after receiving a hepatitis B vaccine, and false negatives can occur in the early stages of infection or in cases of low viral load. Other factors such as the timing of the test post-exposure and the type of assay used can also affect results.

The time to receive HBsAg test reports can vary depending on the laboratory but typically takes 6 hours. Although this may vary depending on the healthcare provider and the time/day when the sample was collected and processed.