What should you know about whether hepatitis B is an STD?

Hepatitis B is an infection caused by a virus that can be present in blood and some body fluids. Sexual contact without effective protection can transmit it. It can also spread through shared needles or equipment, unsterile skin-piercing instruments, accidental needlestick injuries, or contact with infected blood. It is not spread by ordinary social contact such as hugging, sharing food, or sitting beside someone.

A person may have no symptoms, so appearance cannot show whether someone has hepatitis B. Fatigue, nausea, yellowing of the eyes, or dark urine may occur, but these symptoms do not identify the route of infection. See [Hepatitis B](/conditions/hepatitis-b/) for broader information.

Use condoms or other barrier protection until a clinician has assessed the situation, and do not share razors, toothbrushes, needles, or injection equipment. Encourage sexual and household contacts to ask about [Hepatitis B Vaccination](/treatments/preventive-care-and-vaccination/hepatitis-b-vaccination/). Testing can identify infection even when you feel well.

If you have a positive result, tell your clinician about possible exposures and ask how partners can be tested safely. A [Liver Function Test](/treatments/diagnostics-and-screening/liver-function-test/) may be part of assessing your health, but it does not by itself diagnose hepatitis B.

Contact a clinic promptly after sexual contact or blood exposure that could transmit hepatitis B, because early advice may affect testing and prevention. Seek urgent care for confusion, severe vomiting, yellow eyes with rapidly worsening illness, unusual bleeding, or severe abdominal swelling. General information about [Dark Urine](/symptoms/dark-urine/) and [Fatigue](/symptoms/fatigue/) may help you describe symptoms.

Ask whether you need hepatitis B testing, whether your partner or household contacts need vaccination, what protection to use meanwhile, and whether a recent exposure needs urgent preventive care.