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Hepatitis B, Surface Antigen (HBsAg)

Hepatitis B, Surface Antigen (HBsAg)

Test ID: A850-2

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The hepatitis B virus is a common cause of inflammation and damage to the liver. Many individuals with an acute infection remain asymptomatic, but can still pass the virus to others. Chronic infection develops in some infected individuals and can lead to cirrhosis or liver cancer. Laboratory analyses are required for an accurate diagnosis of hepatitis B.

Hepatitis B surface antigen (HBsAg) is the first biomarker to become detectable, usually around four weeks after exposure to hepatitis B. HBsAg remains detectable throughout both acute (short-term) and chronic (long-term) hepatitis B infections, aside from late in an acute infection when a hepatitis B infection is resolving. When an individual has recovered from a hepatitis B infection, HBsAg will no longer be detectable in their blood.



How to order a test


  • HBsAg
  • HBV

What is Included?

Detection of hepatitis B surface antigen (HBsAg) by chemiluminescent microparticle immunoassay.

Turnaround Time

1 – 3 business days
The turnaround time is not guaranteed. The average turnaround time is 1 – 3 business days from the date that the sample arrives at the laboratory. Shipping time for the sample is not included. Additional time is required if the case requires confirmatory or reflex testing, or if the sample is insufficient, or if a recollection is required.

Related Documents

Additional Information and Resources

Special Instructions

Hepatitis B surface antigen (HBsAg) is usually detectable within 30 to 60 days post exposure. A false negative result may occur for specimens collected before HBsAg has reached detectable levels.

NOTE: This test detects active infections (both acute and chronic), but does not detect past exposure to hepatitis B through vaccination or past infection.


Preparation Before Specimen Collection

This test is not recommended within 14 days of receiving the hepatitis B vaccine, as a false-positive result may occur (and can sometimes occur up to 52 days post-vaccination).

Specimen Type



Dried blood spot collection onto 5 circles on the collection card
50 μL in a microtainer


Blood collection card
Microtainer (regular blood tube)

Collection Method

This test requires a blood sample from a finger prick. All supplies for sample collection are provided in the kit.

  1. First wash and dry hands. Warm hands aid in blood collection.
  2. Clean the finger prick site with the alcohol swab and allow to air dry.
  3. Use the provided lancet to puncture the skin in one quick, continuous and deliberate stroke.
  4. Wipe away the first drop of blood.
  5. Massage hand and finger to increase blood flow to the puncture site. Angle arm and hand downwards to facilitate blood collection on the fingertip.
  6. Drip blood onto the blood collection card or into the microtainer tube.
  7. Dispose of all sharps safely and return sample to the laboratory in the provided prepaid return shipping envelope.

NOTES: Avoid squeezing or ‘milking’ the finger excessively. If more blood is required and blood flow stops, perform a second skin puncture on another finger. Do not touch the fingertip.

Specimen Storage

Maintain specimen at temperatures between 2°C and 30°C during storage and transport.

Specimen Stability

  • Dried blood spots can be refrigerated or kept at room temperature for up to 30 days.
  • Blood samples can be refrigerated or kept at room temperature for up to 7 days.

Causes for Rejection

  • Incorrect or incomplete patient identification
  • Incorrect specimen collection
  • Inappropriate storage and transport conditions
  • Incorrect specimen volume



To detect HBsAg in a blood sample for screening for active hepatitis B infections. Follow up testing is required to distinguish acute and chronic infection, and evaluate liver damage, carrier status etc.


  • This report is not intended for use in medico-legal applications.
  • These results are intended for screening and monitoring for hepatitis B, and should be interpreted in conjunction with other laboratory and clinical information.
  • Correct specimen collection and handling is required for optimal assay performance.
  • A negative result does not exclude the possibility of infection. False-negative test results may occur due to improper specimen collection, or specimen collection during the window period post-exposure when HBsAg levels are below detectable limits.
  • A false negative result may occur for an acute infection that is resolving. Additional testing is required to confirm this scenario.
  • A reactive result may occur in the period after hepatitis B vaccination. Usually this is only within 14 days of vaccination, but may occur for up to 52 days after vaccination.
  • Assay interference may occur in specimens from individuals routinely exposed to animals or to animal serum products. Additional clinical or diagnostic information may be required for these specimens.


Chemiluminescent microparticle immunoassay (Alinity i HBsAg Qualitative II)