Overview: Hepatitis B Surface Antigen Quantitative TestIntroduction: The Hepatitis B Surface Antigen Quantitative Test quantifies hepatitis B surface antigen to monitor chronic infection, preventing liver damage. Aligned with 2023 AASLD guidelines, it uses an immunoassay for high sensitivity, aiding in infectious disease screening. This test is critical for guiding antiviral therapy, monitoring treatment response, and improving outcomes in serology for patients with chronic hepatitis B.
Other Names: HBsAg Quant Assay, Quantitative Hepatitis B Antigen Test.
FDA Status: FDA-cleared diagnostic test, meeting serology standards for diagnostic accuracy.
Historical Milestone: Quantitative HBsAg testing began in the 2000s with chronic HBV research. Immunoassays improved in the 2010s, enhancing treatment monitoring.
Purpose: Monitors chronic hepatitis B, guides antiviral therapy, and quantifies HBsAg in patients to prevent liver damage.
Test Parameters: 1. Hepatitis B Surface Antigen (Quantitative)
Pretest Condition: No fasting required. Collect serum at any time. Report history of hepatitis B, treatment status, or symptoms like fatigue, and list medications.
Specimen: 2-5 mL serum (SST). Centrifuge within 1 hour. Transport in a biohazard bag within 8 hours.
Sample Stability at Room Temperature: 8 hours
Sample Stability at Refrigeration: 7 days
Sample Stability at Frozen: 6 months
Medical History: Document fatigue, liver pain, or history of chronic hepatitis B. Include current medications, especially antivirals, and treatment history.
Consent: Written consent required, detailing the tests purpose, monitoring implications, and potential need for treatment adjustments.
Procedural Considerations: Uses an immunoassay to quantify HBsAg levels. Results are available in 1-2 days, enabling rapid clinical decisions.
Factors Affecting Result Accuracy: Hemolysis, improper storage, or recent vaccination can affect results. Treatment status may alter HBsAg levels.
Clinical Significance: High HBsAg levels indicate active chronic hepatitis B, guiding treatment adjustments. Declining levels suggest treatment response.
Specialist Consultation: Consult a hepatologist for result interpretation and antiviral therapy planning.
Additional Supporting Tests: HBV DNA, liver function tests, or anti-HBc to monitor chronic hepatitis B.
Test Limitations: HBsAg levels alone cannot assess treatment response fully. Clinical correlation and HBV DNA testing are needed.
References: AASLD Hepatitis B Guidelines, 2023; Hepatology, Lok AS, 2022.
