Hepatitis B Surface Antigen

• Included in Hepatitis Panel Acute (HABM, HEAGS, HEBCM, HECAB)
• Included in Hepatitis Panel Chronic (HAAB, HBS, HBCAB, HBSAB, HCAB)

1. The assay requires 100 uL of sample for a single determination.
2. Samples are processed by centrifugation, typically followed by physical separation of the serum or plasma from the red cells. When collecting serum specimens, allow tubes to clot adequately before centrifugation. For plasma samples, collect specimens in a well mixed lavender top collection tube. Keep tubes stoppered and upright at all times.
3. The centrifugation step may occur up to 24 hours post draw, otherwise separate the samples immediately.
4. Test samples as soon as possible after collecting. Store processed specimens at 2-8°C if not tested within 24 hours of collection.
5. Store samples in their primary (original draw) tubes (SST, lavender) at 2 – 8⁰ C for up to 14 days, if testing can’t be done within 24 hours of collection. Store samples stoppered at all times. Freeze samples at or below -20⁰ C for longer storage. Specimens may be frozen and completely thawed up to 4 times. Thoroughly mix thawed specimens and centrifuge before using.

Hepatitis B virus (HBV) is endemic throughout the world and is the major cause of liver disease. HBV is transmitted through direct contact with blood and body fluids. Common modes of transmission include blood transfusion, needle puncture, direct contact with open wounds, sexual contact, and mother-neonate contact during birth. The average incubation period for HBV infection is 6 to 8 weeks (range 1 to 6 months). Common clinical symptoms include malaise, fever, gastroenteritis, and icterus. HBV infection can result in typical icteric hepatitis, subclinical anicteric hepatitis, fulminate hepatitis, or chronic or persistent hepatitis. In adults, 90 to 95% of patients with HBV infection completely recover from acute illness and clear the virus. Approximately 5 to 10% of patients with HBV become chronic carriers. In HBV infected neonates, approximately 90% develop chronic hepatitis B infection. It is estimated that over 300 million people worldwide are chronic carriers of the virus. Chronic HBV infection is clearly associated with the development of hepatocellular carcinoma.

Hepatitis B surface antigen (HBsAg) is a distinctive serological marker of acute or chronic hepatitis B infection. HBsAg is the first antigen to appear following infection with hepatitis B virus and is generally detected 1 to 10 weeks before the onset of clinical symptoms. HBsAg assays are routinely used to diagnose suspected HBV infection and to monitor the status of infected individuals to determine whether the infection has resolved or the patient has become a chronic carrier of the virus. In patients that recover from HBV infection, HBsAg levels disappear 3 to 5 months after the onset of the infection. In patients with chronic HBV infection, HBsAg levels may remain detectable for life. Prenatal HBsAg screening has been recommended so that newborns from carrier mothers may obtain prophylactic treatment.