Your hepatitis B panel is read by combining three markers: HBsAg (current infection), anti-HBs (immunity), and total anti-HBc (past or current exposure). HBsAg positive means active infection. Anti-HBs positive alone usually means vaccination. Anti-HBs plus anti-HBc means a resolved past infection. All three negative means no infection and no immunity.
2020–2023, steady
many undiagnosed
protective for 20+ years
vs <5% in adults
| Item | Value |
|---|---|
| Acute cases | ~2,200/yr — 2020–2023, steady |
| Chronic infection | ~640,000+ — many undiagnosed |
| Vaccine | ~100% — protective for 20+ years |
| Infant chronicity | ~90% — vs <5% in adults |
What hepatitis B is, in one breath
Hepatitis B is a vaccine-preventable liver infection caused by the hepatitis B virus (HBV), which spreads mainly through blood and sex CDC, About Hepatitis B. Doctors split it by duration: acute hepatitis B is the short-term illness that shows up in the first six months after exposure, while chronic hepatitis B lasts beyond six months and can be lifelong. The split changes what your test results mean and what happens next. If you're trying to tell this apart from a related infection, see hepatitis b vs hepatitis c.
How hepatitis B is tested
Hepatitis B is diagnosed with a blood draw, not a urine cup or a swab. The standard screen is a triple serologic panel measuring three things at once: HBsAg, anti-HBs, and total anti-HBc CDC, HBV testing. HBsAg is a surface protein the virus sheds while it's actively replicating, so a positive flags active infection. Anti-HBs is the antibody your body makes after you clear the virus or get vaccinated, signaling protection. Total anti-HBc is the antibody to the virus's core, and once it appears it tends to stay for life. It tells a clinician you've met the actual virus at some point, which a vaccine alone never produces.
The sample is a simple venous blood draw, and results typically come back within a few days. At-home and mail-in options exist too, though confirmatory testing for hepatitis B usually means a clinic blood test rather than a finger-prick. You can get tested at a clinic. Ask up front for the full three-marker panel rather than a single HBsAg, so your status is unambiguous.
When to test after exposure
HBsAg doesn't turn positive the day after exposure; the markers need time to rise. Symptoms, when they happen, appear on average about 90 days after exposure, with a range of roughly 60 to 150 days CDC surveillance. During that window period, testing too early can produce a falsely reassuring negative. If you've had a specific recent exposure, read when to test after exposure before you book, and tell the clinic the date so they can time the draw and decide whether you need post-exposure protection now rather than waiting.
Many people with acute hepatitis B feel nothing at all; others get fatigue, nausea, dark urine, or yellowing of the skin and eyes. For the full picture of what to watch for, see hepatitis b symptoms.
Who should get screened
As of the latest guidance, the CDC recommends that every adult aged 18 and older be screened for hepatitis B at least once in their lifetime, regardless of risk, and that pregnant people be screened with HBsAg in each pregnancy CDC, 2023. Universal adult screening is a shift from older risk-based rules. It exists because acute reports have held roughly steady, around 2,200 a year from 2020 to 2023 CDC AtlasPlus, 2023, while hundreds of thousands more people live with undiagnosed chronic infection they can't feel.
- Every adult, at least once — current CDC universal-screening guidance.
- Every pregnancy, because hepatitis B can pass to the baby around birth.
- People with HIV, people who inject drugs, and household or sexual contacts of someone with hepatitis B.
- Anyone born in a region where hepatitis B is common, or born to a parent from one.
Getting tested: what the visit and cost are like
The visit is brief. A clinician asks a few history questions, draws a tube of blood, and sends it for the panel; results are usually back in a few days. Testing is free or low-cost at many health departments, Planned Parenthood, and Title X clinics, and most insurance covers screening with no copay because it's a recommended preventive service. If you'd rather compare home-collection and lab options on price and turnaround, you can compare testing providers.
A hepatitis B diagnosis is common and manageable, clinics handle it routinely, and it says nothing about you as a person. The harder part is usually the waiting.
Reading your hepatitis B test results
The three markers only make sense together. Read across all three, not one at a time, because a single positive in isolation can point in opposite directions depending on what the other two show. Use this decoder:
| HBsAg | anti-HBs | total anti-HBc | What it means |
|---|---|---|---|
| Negative | Negative | Negative | Susceptible — never infected, not immune. Consider the vaccine. |
| Negative | Positive | Negative | Immune from vaccination — protected, never infected. |
| Negative | Positive | Positive | Immune from past infection that resolved — recovered. |
| Positive | Negative | Positive | Currently infected (acute or chronic). Needs follow-up testing. |
| Negative | Negative | Positive | Unclear — could be resolving infection, a faint old infection, or a false positive. Repeat/expanded testing needed. |
A couple of patterns are worth spelling out. If only anti-HBs is positive, you almost certainly got there through a vaccine, since the vaccine uses the surface protein and never exposes you to the core, so it can't make anti-HBc. When both anti-HBs and anti-HBc are positive but HBsAg is negative, your immune system met the real virus and cleared it; you're recovered and protected. A positive HBsAg by itself can't tell acute from chronic. That takes a repeat HBsAg after six months and additional tests your clinician will order.
If your result is positive
A positive HBsAg means active infection and earns a real conversation with a clinician. Age at infection drives the outcome: caught in adulthood, hepatitis B becomes chronic in under 5% of people, while about 95% of adults clear it on their own. Chronic infection is controlled rather than cured. Antivirals such as tenofovir or entecavir suppress the virus and cut liver-cancer risk, but most people take them for the long term AASLD, 2018. The full regimen, monitoring schedule, and what daily treatment is actually like belong on the treatment page; finish whatever course you're prescribed and ask whether partners need testing or the hepatitis vaccines so you're not passing it back and forth.
When to see a clinician
See a clinician promptly if your HBsAg comes back positive, if you have a known recent exposure (so post-exposure prophylaxis can be started without delay), if you're pregnant, or if you have yellowing skin, severe nausea, confusion, or persistent abdominal pain, all signs the liver is struggling. If you're pregnant and HBsAg-positive, this matters enormously for the baby: hepatitis B most often passes to a child around the time of birth, and an infant infected then has about a 90% chance of lifelong infection CDC perinatal. Prevention is highly effective. The newborn vaccine plus hepatitis B immune globulin within hours of birth prevents most transmission perinatal meta-analysis, and that is why every pregnancy is screened.