Hepatitis B virus (HBV) surface antigen - serum specimen
- LIS Mnemonic: HBVSAG
Collect
Gold (SST - Clot activator & gel)
Volume Required
2 ml blood
Minimum Required
1 ml serum
Transport
A total of 2-4 ml of blood (for every 2-3 HIV and Hepatitis tests ordered) should be collected and submitted at room temperature to the laboratory.
Days Performed
Monday thru Friday
Reported
Daily
Reflex Testing
Hepatitis B surface antigen confirmation assay. All specimens that test repeatedely positive for Hepatitis B surface antigen by the screening enzyme immunoassay must be confimed by a neutralization assay.
CPT
87340 (initial screening),87341 (confirmation assay, if necessary)
Methodology
Microparticle Enzyme Immunoassay
Disease Information
Utility:
A test for HBsAg is indicated as an aid in the laboratory diagnosis of acute, chronic, or resolved hepatitis B viral infection. Detection of HBsAg indicates the presence of HBV but does not distinguish between acute and chronic infection. During acute HBV infection, HBsAg appears 3-5 weeks before the onset of symptoms, peaks during the acute phase of the disease, and slowly declines to undetectable levels within 4-6 months. Persistance of HBsAg for 6 months or longer after acute illness is indicative of chronic infection. HBsAg can be detectable for life in most chronically infected individuals; only 1-2% of chronic HBV carriers become negative for HBsAg each year. The HBsAg assay also may be used to test for HBV infection in pregnant women. Prenatal testing has been recommended so that newborns from mothers who are HBV carriers may receive appropriate prophylactic treatment.
Interpretation
HBV surface antigen is the earliest indicator of the presence of acute infection; it is also indicative of chronic infection. A hepatitis B core IgM antibody test and an HBV core total antibody (IgG & IgM) test should also be ordered to help differentiate acute from chronic HBV infection. Negative results for HBsAg indicates no evidence of a recent or chronic infection with HBV. This does not exclude the possibility of exposure to or early acute infection with HBV. If clinically indicated, please wait 1-2 weeks and submit another specimen for additional HBV surface antigen testing. A hepatitis B core IgM antibody test may also be ordered on the current and repeat specimens. Patients with possible HBsAg mutations may be nonreactive for HBsAg. If acute or chronic HBV infection is suspected, and the HBsAg result is nonreactive, it is recommended that other HBV serological markers and HBV DNA be tested to confirm the HBsAg nonreactivity. For diagnostic purposes, HBsAg reactivity should be correlated with patient history and the presence of other hepatitis markers.
Reference Values
Negative or non-reactive for hepatitis B Virus (HBV) surface antigen
Remarks
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