Hepatitis B Surface Antigen

CPT: 87340
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Test Details

Synonyms

  • Hepatitis-associated Antigen

Test Includes

Confirmation of a positive result by a neutralization assay at no additional charge

Use

Test blood donors (HBsAg positive individuals are rejected). Hepatitis B surface antigen is the earliest indicator of the presence of acute infection. Also indicative of chronic infection. Test is useful in the differential diagnosis of hepatitis.

Limitations

Patients who are negative for HBsAg may still have acute type B viral hepatitis. There is sometimes a “core window” stage when HBsAg has become negative and the patient has not yet developed the antibody (anti-HBs). On such occasions, both tests for anti-HBc are usually positive and anti-HBc, IgM is the only specific marker for the diagnosis of acute infection with hepatitis B. In cases with strong clinical suspicion of viral hepatitis, serologic testing should not be limited to detecting HBsAg, but should include a battery of tests to evaluate different stages of acute and convalescent hepatitis.

Methodology

Immunochemiluminometric assay (ICMA)

Reference Interval

Negative

Additional Information

Hepatitis B virus (HBV) is a DNA virus with a protein coat, the surface antigen (HBsAg) and a nucleic acid core, the core antigen (HBcAg). There are eight different serotypes. Early in infection, HBsAg, HBV DNA, and DNA polymerase can all be detected in serum.

HBsAg can be detected one to seven weeks before liver enzyme elevation or the appearance of clinical symptoms. Three weeks after the onset of acute hepatitis, about 50% of patients will still be positive for HBsAg, while at 17 weeks only 10% are positive. The best available markers for infectivity are HBsAg and HBeAg. The presence of anti-HBs is frequently associated with noninfectivity. The chronic carrier state is indicated by the persistence of HBsAg and/or HBeAg over long periods (six months to years) without seroconversion to the corresponding antibodies. Such a condition has the potential to lead to serious liver damage, but may be an isolated asymptomatic serologic phenomenon.

Persistence of HBsAg, without anti-HBs, with combinations of positivity of anti-HBc, HBeAg, or anti-HBe indicates infectivity and need for investigation for chronic persistent or chronic aggressive hepatitis. See figure in Hepatitis B Core Antibody, IgM [016881].

Specimen Requirements

Specimen

Serum or plasma

Volume

3.5 mL

Minimum Volume

1.5 mL (Note: This volume does not allow for repeat testing.)

Container

Red-top tube, gel-barrier tube, or lavender-top (EDTA) tube

Collection

If tube other than a gel-barrier tube is used, transfer separated serum or plasma to a plastic transport tube.

Storage Instructions

Room temperature

Stability Requirements

Temperature

Period

Room temperature

14 days

Refrigerated

14 days

Frozen

14 days

Freeze/thaw cycles

Stable x3

Causes for Rejection

Non-EDTA plasma specimen; PST gel-barrier tube

Clinical Information

Special Instructions

This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample.

References

Edwards MS. Hepatitis B serology-Help in interpretation. Pediatr Clin North Am. 1988 Jun; 35(3):503-515 (review). 3287312
Favero MS, Maynard JE, Leger RT, Graham DR, Dixon RE. Guidelines for the care of patients hospitalized with viral hepatitis. Ann Intern Med. 1979 Dec; 91(6):872-876. 517890
Lee HS, Vyas GN. Diagnosis of viral hepatitis. Clin Lab Med. 1987 Dec; 7(4):741-757 (review). 3319367
Mushahwar IK, Dienstag JL, Polesky HF, McGrath LC, Decker RH, Overby LR. Interpretation of various serological profiles of hepatitis B virus infection. Am J Clin Pathol. 1981 Dec; 76(6):773-777. 7315794

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
006510 HBsAg Screen 5196-1 006510 HBsAg Screen 5196-1
Reflex Table for HBsAg Screen
Order Code Order Name Result Code Result Name UofM Result LOINC
Reflex 1 016105 HBsAg Confirmation 016105 HBsAg Confirmation 7905-3

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