Details

Hepatitis B Surface Antigen (HBsAg)

Antrim #31315, EPIC: LAB5222, SOFT: HBSAG

Specimen Collection Criteria

Collect (preferred specimen): One Gold-top SST tube. (Minimum Whole Blood: 4.0 mL)
Also acceptable: One Lavender-top EDTA tube. (Minimum Whole Blood: 3.0 mL)

Note: Patient Preparation (Royal Oak ONLY): Twenty-four (24) hours before this test, the patient should not take multivitamins or dietary supplements containing biotin (vitamin B7) which is commonly found in hair, skin and nail supplements and multivitamins.

Physician Office/Drawsite Specimen Preparation

  • Let SST specimens clot 30-60 minutes then immediately centrifuge to separate serum from cells. Refrigerate (2-8°C or 36-46°F) the centrifuged SST tube within two hours of collection. (Min: 2.0 mL)
  • Centrifuge Lavender-top tube immediately to separate plasma from cells. Transfer plasma to a plastic transport tube and refrigerate (2-8°C or 36-46°F) within twelve hours of collection. (Min: 2.0 mL) 

Preparation for Courier Transport

Transport: Centrifuged SST tube or plasma aliquot, refrigerated (2-8°C or 36-46°F). (Min: 2.0 mL serum or plasma)

Rejection Criteria

  • Hemolyzed specimens.
  • Severely lipemic specimens.
  • Red-top tubes with serum not separated from cells within two hours of collection.
  • Lavender-top tubes with plasma not separated from cells within twelve hours of collection.

Storage

Centrifuged SST tubes may be transported and stored at ambient temperatures (2o to 30oC; 36o to 86oF) for up to 48 hours. DO NOT FREEZE TUBES CONTAINING BLOOD. For longer storage, the serum should be removed from the gel and refrigerated (2o-8oC) or frozen at -20o C or below.

Red-top tubes and Microtainers® may be stored at ambient temperatures for up to 16 hours and for up to 3 days at refrigerator temperatures (2o -8oC).DO NOT FREEZE TUBES CONTAINING BLOOD. For longer storage, the serum should be removed from the clot and refrigerated (2o-8oC) or frozen at -20o C or below.

Lavender top tubes can be stored at ambient temperatures (2o to 30oC; 36o to 86oF) for up to 12 hours.

Serum and plasma (pour-overs) may be stored at room temperature (20o to 26o C; 68o to 79o F) for up to 5 days, refrigerator temperature (2o to 8oC; 36o to 47o F) for two weeks, and at -20oC (-4o F) for up to 3 months. Specimens stored at -70o C (-94o F) can be stored indefinetly.

Performed

Sunday - Saturday, 24 hours a day.
STAT results (Labor and Delivery ONLY) available within 4 hours of receipt in the Laboratory.
Routine results available within 24 hours of receipt in the Laboratory.

Reference Range

Negative/Non-reactive.

Test Methodology

Chemiluminescence Immunoassay.

Interpretation

  • Non-reactive: No HBsAg detectable.
  • Reactive: Confirmatory testing will be performed on all positive specimens using neutralizing antibodies.
  • HBsAg detection methods are not sensitive enough to detect all potentially infectious units of blood or possible cases of hepatitis.
  • False-reactive results may be caused by particulate matter in the patient specimen, particularly fibrin clots and cellular material. Serum from heparinized patients may be incompletely coagulated and false reactives could occur due to the presence of fibrin on the reaction cell matrix. Draw serum prior to heparin therapy or draw specimen into a plasma collection tube to prevent this phenomenon.

Clinical Utility

  • HBsAg assay is used to aid in the diagnosis of hepatitis B, to monitor the status of infected individuals (i.e., whether the patient has resolved infection or has become a chronic carrier of the virus), and to evaluate the efficacy of anti-viral drugs. The CDC recommends a prenatal screening of all pregnant women so that newborns from HBV carrier mothers may obtain prophylactic treatment.
  • The incubation period for hepatitis B is approximately 70 days (range, 30 - 180 days). (1)
  • HBsAg appears in the serum 2-7 weeks before the onset of symptoms. It usually persists in the blood throughout the illness and disappears with convalescence. (1)

Clinical Disease

  • Patients with hepatitis B may present with fatigue, poor appetite, fever, vomiting and occasionally joint pain, hives or rash. Urine may become darker in color, and then jaundice (a yellowing of the skin and whites of the eyes) may appear. Patients may also be asymptomatic or experience only a few symptoms.
  • Hepatitis B infections (HBV) are found worldwide. It is the most prevalent type of acute hepatitis worldwide. Persistent infection with the virus is common. In highly endemic areas approximately 10% of the population are chronic carriers of HBV. The number of chronic carriers worldwide exceeds 230 million. (2)

Reference

  1. Hsu, H., Feinstone, S., Hoofnagle,J . Acute Viral Hepatitis in Mandell, G., Bennett, J., Dolin. R.(eds.), Principles of Infectious Diseases 7th edition New York,N.Y. 2005 Chapter 115,116.
  2. Farrar, W., Wood, M., Innes, J., Tubbs, H. Infectious Diseases, Time Mirror International Publishers Ltd New York, N.Y. 1995.

CPT Code

87340.

Test Codes

Antrim #31315, EPIC: LAB5222, SOFT: HBSAG

Last Updated

7/11/2019