Hepatitis B Surface Antigen (HBsAg)
Shows an active hepatitis B infection and whether the virus is transmissible.
Consider this test if:
- Unexplained elevated liver enzymes or symptoms like jaundice, fatigue, abdominal pain, or dark urine
- A known or possible exposure to hepatitis B through blood, sexual contact, or shared needles
- Screening during pregnancy or before starting immunosuppressive or chemotherapy treatment
- Confirming infection status before or after hepatitis B vaccination
- Living with or coming from a region where hepatitis B is common
- HSA/FSA eligible
- Typical results in 1-2 days · Reviewed by a real clinician
- Drawn at a CLIA/CAP-accredited lab near you ·
Pre-test considerations
No fasting required and timing does not affect the result. Recent hepatitis B vaccination does not turn this antigen test positive, so vaccination history does not interfere. A positive screen is confirmed with an additional reflex test before it is considered diagnostic.
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What this test is for
Hepatitis B surface antigen (HBsAg) is a protein on the outer coat of the hepatitis B virus, and its presence in blood means an active HBV infection, whether recently acquired or long-standing and chronic. It is usually the first marker to appear, often before liver enzymes rise or symptoms like fatigue, jaundice, abdominal pain, or dark urine show up, and a positive result also means the infection is transmissible to others. Chronic HBV is the main concern, since it can progress quietly over years to cirrhosis and liver cancer, which is why a positive HBsAg is confirmed and then followed over time.
This test detects current infection. It differs from the hepatitis B surface antibody test, which indicates immunity from vaccination or a resolved infection, and from the core antibody test, which marks past or current exposure; together those three answer different questions about HBV status.
What to expect
- 1 Book instantly
Click, book, done. Choose a convenient lab location near you. Transparent, up-front pricing.
- 2 Quick lab visit
Testing to fit your busy schedule, usually 15 minutes or less. Walk-in and appointments available.
- 3 Typical results in 1-2 days
Your results post straight to your dashboard as soon as the lab completes them.
- 4 Expert guidance
Included with Mito membership. A clinician reviews your results and your personalized action plan follows, with clear next steps.
Everything your health needs,
in one membership
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Every test at our cost
Members pay our cost on every test, with lab fees passed straight through. The full receipt is itemized, never padded.
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Continuous tracking, all in one place
Upload past labs and watch your trends over time. Every marker and visit lives in one longitudinal record, so all your care stays together.
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Year-round clinician support
Text anytime and get clinician-reviewed answers. When you want to go deeper, 1:1 consultations are available at affordable rates.
All for $9/month
Order any test or consult without joining. For $9/month, members unlock member prices, trend tracking, and year-round clinician guidance.
Mito Membership
$9 /mo
cancel anytime
Without membership
$0
pay as you go
At-cost pricing on labs, scans, and more
Priority turnaround on your results
On-demand clinician consults when you need guidance
Personalized action plans across supplements, exercise, nutrition, and sleep
AI health coaching to help you act on your results
Year-round medical support, with in-chat clinician escalation
All your health records in one personal vault, with trends and biological age tracking
Early access to new diagnostics and product releases
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Frequently asked questions
View all FAQsHow does pricing work?
Every test shows the member price next to the standard non-member price, so you can see what membership saves you. The member price is our cost — covering the lab and what it takes to run the service — never a profit on the test itself; Mito makes its money on the $9 membership, not on marking up your tests. Membership is $9/mo, and you still pay the lab’s order fee. Prices are itemized before you pay, with no hidden fees.
Where do I get tested?
Choose a partner lab (Quest, Labcorp, or BioReference) at checkout. If your cart spans multiple tests, we consolidate the whole order onto a single lab so you only make one visit.
Is this eligible for HSA/FSA?
Yes. This test is HSA/FSA eligible, and you can pay with your HSA/FSA card at checkout.
When will I get my results?
Your results post to your dashboard once your lab completes them, then a clinician reviews them and your full analysis and personalized action plan (with clear next steps) follow. Turnaround varies by test: specialty assays and at-home kits take longer, and each test shows its expected turnaround before you buy.
Do I need a doctor’s order?
No. Mito provides the lab order for you, so you can book and get tested without a separate doctor visit.
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