Hepatitis B virus (HBV)
DNA PCR test

How does hepatitis B spread, and who is most at risk?

The infection spreads only through infected body fluids (blood, semen, vaginal fluid, saliva and urine), by direct contact or through the mucous membranes. Because the amount of virus in body fluids is extremely high in the acute (early) phase, even a tiny amount of infectious material is enough to cause illness.

People at higher risk of infection include:

• People with a promiscuous lifestyle (several sexual partners, sex without a condom).
• People who have had a tattoo or piercing in non-sterile conditions.
• Healthcare workers (because of their daily work and possible needlestick injuries).
• People who inject drugs (sharing needles).
• Close family members living in the same household as an infected person.

Symptoms of infection: why is it hard to spot in time?

The incubation period of hepatitis B is long, usually 1–3 months. The virus itself does not directly destroy liver cells, so in the early stage of infection the symptoms are often very mild, non-specific or even completely absent (about 30% of infections cause no symptoms at all).

Which warning signs call for a test?

• General symptoms: Prolonged, severe tiredness, exhaustion, general weakness and low energy.
• Early symptoms: A raised temperature, fever, joint pains that move around, or typical skin rashes.
• Specific liver symptoms: Yellowing of the whites of the eyes or the skin (jaundice), dark urine and digestive problems.

Why is a PCR test needed alongside a standard blood test?

The basic way to detect hepatitis B is traditional antibody and antigen testing (the ELISA method), which looks for the virus’s surface proteins (HBsAg) or the antibodies the body makes. In some situations, however, this alone is not reliable enough:

• Bridging the window period: After infection there is a period (the window period) when the body has not yet made enough protein or antibodies, so a traditional test will be falsely negative. The PCR test looks for the virus’s DNA, so it shortens this period and can confirm the infection much earlier.
• Identifying mutant strains: In some cases (for example in people of Mediterranean origin or with so-called core mutations) the structure of the virus changes. Traditional tests then stay "blind" to the infection, while PCR still gives a pinpoint-accurate result.
• Starting and monitoring treatment: Under modern international guidelines, deciding whether to start hepatitis B treatment, and checking how well the medicines work, requires an accurate viral load (copy number), which only a PCR test can measure.

What should you do after you receive the test result?

The cornerstone of hepatitis B diagnosis is mapping the serological profile, which the PCR test completes.

• If the result is positive: If the PCR test detects the virus, contact your doctor straight away with the result; we also recommend visiting your regional Hepatology Centre (liver clinic). There, based on the exact copy number and the full set of results, specialists will make a precise diagnosis and decide on the best personalised antiviral treatment to protect your liver in the long term.