Hepatitis B Surface Antigen with Reflex Confirmation
Also known as: Australian Antigen, Hep B, HBsAg
Use
Hepatitis B Surface Antigen (HBsAg) typically appears in the serum 1–6 months after exposure to hepatitis B virus and peaks shortly after symptoms begin. If HBsAg persists for more than 6 months, it indicates chronic HBV infection. This test detects acute or chronic infection and includes reflex confirmation per manufacturer’s FDA‑approved recommendations when surface antigen is positive.
Special Instructions
Dietary biotin supplements may interfere with assay performance. For routine biotin doses, draw sample at least 8 hours after last supplementation; for mega‑dose biotin, draw at least 72 hours post‑dose.
Limitations
Results in immunosuppressed patients should be interpreted with caution. Patients receiving mouse antibody therapy may yield false‑negative results. Gross hemolysis or gross lipemia can lead to specimen rejection.
Methodology
Immunoassay (IA)
Biomarkers
LOINC Codes
- 5196‑1
- 7905‑3
Result Turnaround Time
2-4 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
2 mL preferred; minimum 1 mL
Minimum Volume
1 mL
Container
Serum (red‑top tube); SST acceptable
Collection Instructions
Serum preferred; plasma in EDTA (lavender‑top) tube also acceptable.
Patient Preparation
Avoid biotin interference: draw ≥8 hours after routine biotin, ≥72 hours after mega‑dose.
Causes for Rejection
Gross hemolysis; gross lipemia
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 14 days |
| Frozen | 30 days |
Other tests from different labs that may be relevant