HBV Risk Estimator
Before you begin:
Are you currently experiencing symptoms or have you recently been in contact with someone who tested positive?
This tool estimates risk based on demographic and lifestyle factors for people without known symptoms or exposure. It is not designed to assess the likelihood of infection after a specific exposure or to evaluate active symptoms.
If you have symptoms or known exposure, lab testing is the appropriate next step. A healthcare provider can order the right tests and interpret the results for your situation.
Hepatitis B virus (HBV) is transmitted through blood and bodily fluids and can cause chronic liver infection, cirrhosis, and liver cancer. An effective vaccine has been available since 1982 and is now part of the standard childhood immunization schedule in the US.
This calculator estimates the probability of ever having been infected with HBV (core antibody positive), using a gradient-boosted classifier trained on NHANES serology data (2005–2016, ~44,500 participants). The core antibody test (anti-HBc) distinguishes natural infection from vaccine-derived immunity, since vaccination produces surface antibodies (anti-HBs) but not core antibodies.
Your percentage represents the estimated probability that a person with your profile has HBV core antibodies, indicating past or current natural infection. The red line on the gauge shows the US population average (~5.4%). This estimate reflects natural infection only and is not affected by vaccination status.
This calculator estimates the probability that you have HBV core antibodies (anti-HBc), indicating past or current natural infection. It uses patterns from NHANES serology data. It does not diagnose Hepatitis B or determine whether an infection is active.
No. This calculator estimates natural infection using the core antibody (anti-HBc) as its outcome. The HBV vaccine produces surface antibodies (anti-HBs) but not core antibodies, so vaccination status does not affect the model's prediction. However, if you are vaccinated, your actual risk of future infection is much lower than what the calculator estimates.
The CDC recommends HBV screening for all adults at least once, pregnant women during each pregnancy, people born in regions with HBV prevalence of 2% or higher (most of Asia, Africa, and the Pacific Islands), household and sexual contacts of HBV-positive individuals, people who inject drugs, and people with HIV. You can order a Hepatitis B test online through STDCheck.com.
A standard HBV blood panel includes three markers: surface antigen (HBsAg, indicates current infection), surface antibody (anti-HBs, indicates immunity from vaccination or past infection), and core antibody (anti-HBc, indicates past or current natural infection). Together, these determine your infection and immunity status.
HBV is transmitted through blood, semen, and other bodily fluids. Common routes include perinatal transmission (mother to child at birth), sexual contact, sharing needles, and household contact with an infected person. HBV is far more infectious than HCV or HIV — it can survive outside the body for at least 7 days.
Most adults who acquire HBV clear the infection on their own within 6 months. However, about 5% of adults (and up to 90% of infants) develop chronic HBV. Chronic HBV can be managed with antiviral medications to reduce liver damage but is rarely cured completely. Prevention through vaccination is the most effective strategy.
HBV is endemic in many parts of Asia, sub-Saharan Africa, and the Pacific Islands, where prevalence can exceed 8%. People born in these regions may have been exposed perinatally or in early childhood, before vaccination programs were established. In the NHANES data, being born outside the US is the single strongest predictor of HBV core antibody positivity.
See a healthcare provider if you were born in a high-prevalence region and haven't been tested, if you are a household or sexual contact of someone with HBV, if you have symptoms of liver disease (jaundice, fatigue, abdominal pain), or if you are unsure of your vaccination status. A simple blood panel can determine your infection and immunity status — STDCheck.com offers confidential HBV testing with results in 1-2 days.
Compare testing options — online lab orders, free clinics, and more. Find the right fit for your situation.
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