Hepatitis B Surface Antigen
Label Mnemonic: HBSG
Epic Lab Code: LAB625
Downtime Form: A-1a General Laboratory Requisition
Chemistry
6240 RCP
356-3527
Specimen(s):
Plasma
Collection Medium:
Plasma Separator Tube 4.5 mL
Alternate Collection Media:
Call laboratory for additional acceptable specimen collection containers.
Minimum:
3 mL whole blood from light green top tube or TWO Microtainer® devices for pediatric patients.
Testing Schedule:
24 hrs/day, 7 days a week, including holidays.
Turn Around Time:
1 hour (upon receipt in laboratory)
Reference Range:
Negative
Comments:
Part of initial diagnostic hepatitis profile. May be ordered separately.
Negative: <1.0

Samples with weak but repeatedly positive reactivity (cutoff index greater than or equal to 1.0 but less than or equal to 20) will be resulted as "GRAYZONE". If sufficient specimen is available, samples with GRAYZONE reactivity will be analyzed by the hepatitis B surface antigen neutralization test (a confirmatory test) by a reference laboratory. A negative surface neutralization reaction indicates that the patient does NOT have a positive surface antigen test. If insufficient sample is available for the neutralization confirmatory test, the pathology resident or attending will contact the ordering physician to discuss the results.
Positive: >20.0

New analytical immunoassay instituted April 5, 2010.

This test is also performed in the Iowa River Landing (IRL) clinical laboratory (for specimens drawn at that site).
Test Limitations:
Assay is unaffected by icterus (<60 mg/dL), hemolysis (Hb < 1400 mg/dL), and lipemia (triglycerides < 1500 mg/dL). In patients receiving high biotin doses (> 5 mg/day) no sample should be taken until at least 8 hours after the last biotin administration. No false negative findings due to the high-dose hook effect are observed up to a HBsAg concentration of 1.5 million IU/mL. In rare cases, interference due to extremely high titers of antibodies to analyte-specific antibodies, streptavidin, or ruthenium can occur.

For diagnostic purposes, the results should always be assessed in conjunction with the patient's medical history, clinical examination, and other findings. The assay is not intended for use in screening blood bank donors. A negative test result does not exclude the possibility of exposure to or infection with hepatitis B. Negative test results in individuals with prior exposure to hepatitis B may be due to antigen levels below the detection limit of this assay or lack of antigen reactivity to the antibodies used in this assay.

False positive reactions may occur rarely in patients with rheumatologic disease (due to presence of auto-antibodies) or in kidney failure. Individuals recently vaccinated for hepatitis B may give a transient positive result for HBsAg because of its presence in the vaccine. The ability of the Elecsys HBsAg assay to detect hepatitis B virus mutants has not been determined. Testing using alternative methodologies may be warranted if signs, symptoms, and risk factors are indicative of viral hepatitis and other laboratory tests are negative for the presence of viral hepatitis.
Methodology:
Electrochemiluminescence Immunoassay (ECLIA)
CPT Code:
87340