In shortHepatitis B is read from three markers: HBsAg — the virus in blood now; anti-HBs — protective antibodies (after vaccination or a past infection); anti-HBc — a trace of a real encounter (vaccination does not produce it). Their combination tells: infection, past disease, immunity or vulnerability.
About the infection
Hepatitis B virus spreads with blood and body fluids: medical and cosmetic procedures, sexual contact, mother to child. Acute hepatitis may pass unnoticed, and in some people the virus persists and turns chronic.
Diagnostics rests on markers — viral proteins and antibodies to them. Their combination shows not only “yes/no” but the stage: acute infection, chronic carriage, immunity after vaccination or after disease.
Diagnostic methods
| Method | What it shows | When it is used |
|---|---|---|
| HBsAg (Australia antigen) | Viral envelope protein — virus in blood now | Screening: pregnancy, donors, before surgery; “+” — active infection |
| anti-HBs | Protective antibodies to the envelope | Immunity check: after vaccination ≥ 10 IU/L means protection |
| anti-HBc (total and IgM) | Antibodies to the viral core — a trace of a real encounter | Tells a past infection from vaccination; IgM — acute phase |
| HBV DNA (PCR) and HBeAg | Viral replication activity | With confirmed HBsAg — for treatment decisions |
Window period: when the test becomes reliable
HBsAg appears in blood 1–9 weeks after infection (about a month on average). If the contact was recent and screening is negative, with high risk the test is repeated in 1.5–3 months.
How to prepare
Venous blood fasting or 4 hours after a meal. No special preparation. To check post-vaccination immunity, anti-HBs is taken no earlier than 1–2 months after the last dose.
Reading the result
| Result | What it means |
|---|---|
| HBsAg “+” | Virus in blood — acute or chronic infection: see a hepatologist/infectious disease specialist, then HBV DNA and liver tests |
| HBsAg “−”, anti-HBs ≥ 10 IU/L, anti-HBc “−” | Post-vaccination immunity — protection present |
| HBsAg “−”, anti-HBs “+”, anti-HBc “+” | Past hepatitis B, no virus, immunity present |
| All negative | No encounter and no protection — vaccination is indicated |
| anti-HBc IgM “+” | Acute or recent infection — see a doctor promptly |
When a retest makes sense
With a recent risky contact and negative HBsAg — repeat in 1.5–3 months. A chronic HBsAg carrier is monitored regularly: liver tests and HBV DNA on the doctor’s schedule.
Which specialist to see
A positive or doubtful result is reviewed by: Hepatologist, infectious disease specialist, primary care physician. Note the date of the first test and the possible contact — the retesting plan depends on it.
Several markers on your report?
The app reads your whole report — this marker together with its neighbors, not one by one.
Frequently asked questions
HBsAg positive — is it chronic hepatitis?
Not necessarily: HBsAg appears in the acute phase too. Chronic is when HBsAg persists beyond 6 months. Next come viral DNA, HBeAg and liver enzymes — they drive the treatment decision.
Will hepatitis B vaccination give a positive test?
Vaccination produces only anti-HBs — that is its goal (protection at ≥ 10 IU/L). HBsAg and anti-HBc should not appear after vaccination: their presence means a real encounter.
Does hepatitis B spread by household contact?
Handshakes, dishes and hugs — no. Routes: blood (manicure, tattoos, dentistry, shared needles), unprotected sex, mother to child at birth.
Sources
- MedlinePlus — Hepatitis Panel — MedlinePlus (medlineplus.gov). Accessed: September 17, 2026.
- MSD Manuals — Helminths — MSD Manuals (msdmanuals.com). Accessed: September 17, 2026.