Hepatitis testing is done through blood tests that look for antibodies, viral proteins, or viral genetic material. Most people start with a simple blood draw that checks for hepatitis A, B, and C at the same time, and results typically come back within a few days. The specific tests you need depend on whether you’re screening without symptoms, investigating possible exposure, or monitoring a known infection.
The Acute Hepatitis Panel
When a doctor suspects a new hepatitis infection, the standard first step is an acute hepatitis panel. This single blood draw tests for all three common types at once. It includes a hepatitis A IgM antibody (detecting a current or very recent infection), a hepatitis B surface antigen and core antibody IgM (identifying active hepatitis B), and a hepatitis C antibody (screening for exposure to the virus). If the hepatitis C antibody comes back positive, the lab automatically runs a follow-up test on the same sample to check for the actual virus.
This panel does not include liver enzyme tests. Those are usually ordered separately. During acute viral hepatitis, liver enzymes called ALT and AST often spike to 400 IU/L or higher. ALT tends to run higher than AST, though the exact numbers don’t reliably predict how severe the illness will be. These enzyme levels rise early, peak before jaundice is at its worst, and gradually fall during recovery.
How Hepatitis A Testing Works
Hepatitis A testing is straightforward. A positive IgM antibody means you have a current or very recent infection. Once you recover, your body produces a different antibody (IgG) that stays in your blood for life and signals immunity. If both IgM and IgG are positive, you’re dealing with an active or recently resolved infection. If only IgG is positive and IgM is negative, you either recovered from a past infection or were vaccinated. If both are negative, you’ve never been infected and aren’t immune.
One quirk worth knowing: high doses of biotin (a supplement sometimes taken for hair and nails) can interfere with the test and produce false results. If you take biotin supplements, mention it before testing.
How Hepatitis B Testing Works
Hepatitis B uses the most complex set of blood markers because the results need to distinguish between several very different situations: a new infection, a chronic infection, natural immunity from a past infection, and vaccine-induced immunity.
Three markers do most of the work:
- Surface antigen (HBsAg): A protein on the virus’s outer shell. If this is positive, the virus is actively present in your blood, either from a new or chronic infection.
- Surface antibody (anti-HBs): Your immune system’s response to the virus’s surface. If this is positive and the surface antigen is negative, you’re immune, either from vaccination or from clearing a past infection.
- Core antibody (anti-HBc): Produced during infection but not after vaccination. The IgM version indicates a new infection. The total version (without IgM) shows up in anyone who has ever been infected, whether they cleared the virus or not.
The combination tells the story. All three markers negative means you’ve never been exposed and aren’t vaccinated. Surface antibody positive with everything else negative means you’re immune from vaccination. Surface antigen positive with a positive core antibody IgM means you have an acute infection. Surface antigen positive with a positive total core antibody but negative IgM means the infection has become chronic.
If chronic hepatitis B is confirmed, a quantitative viral load test measures the amount of viral DNA in your blood. This test can detect levels as low as 10 IU/mL and as high as 1 billion IU/mL. It helps distinguish active disease from an inactive carrier state and is used repeatedly over time to track whether the virus is being controlled, either by your immune system or by treatment.
How Hepatitis C Testing Works
Hepatitis C uses a two-step process. The first test looks for antibodies, which tell you whether your body has ever encountered the virus. The standard lab-based antibody test has a sensitivity of about 98% and specificity above 99%, meaning it catches nearly all infections and rarely gives false positives.
A positive antibody result does not mean you currently have hepatitis C. About 15 to 25 percent of people who get infected clear the virus on their own, but their antibodies remain forever. So a second test is required: a nucleic acid test (often called a PCR test) that looks for the virus’s actual genetic material in your blood. If this test is positive, the virus is present and the infection is active. If it’s negative, you either cleared the virus naturally or were successfully treated in the past.
Rapid and At-Home Tests
A rapid fingerstick test for hepatitis C, called OraQuick, was FDA-approved in 2010 and can be used as an alternative to the standard lab-based antibody test. It uses a small drop of blood from a finger prick and provides results quickly, making it useful in community health settings, mobile clinics, and other locations without full lab facilities. Like the standard antibody test, a positive rapid result still needs to be confirmed with a PCR test.
The FDA also recognizes home collection kits for hepatitis testing. These kits let you collect a blood sample at home (typically by pricking your finger and placing drops on a collection card) and mailing it to a certified lab. They offer privacy and convenience, but they’re meant to supplement medical care, not replace it. If you use a home kit, make sure it’s authorized for sale in the United States.
Who Should Get Tested
The CDC recommends that all adults 18 and older be screened for hepatitis C at least once in their lifetime. Pregnant women should be tested during each pregnancy. Beyond that baseline, certain groups should be tested regardless of whether they have symptoms:
- People who currently inject drugs or have ever injected drugs and shared equipment
- People living with HIV
- Anyone on long-term hemodialysis
- People who received blood transfusions, organ transplants, or clotting factor concentrates before 1992
- Healthcare workers who’ve had needlestick injuries or blood exposure
- Infants born to mothers with hepatitis C
People who currently inject drugs or receive hemodialysis should be tested periodically, not just once, because of ongoing risk. And anyone who simply wants a hepatitis test can and should receive one. The CDC explicitly states that clinicians should test anyone who asks, regardless of whether they disclose a risk factor, because people are often reluctant to share stigmatizing exposures.
Timing Matters
No hepatitis test is accurate the day after exposure. Each test has a window period, the time between infection and when the test can reliably detect it. Antibody tests generally take longer to turn positive than tests that look directly for the virus. If you’ve had a specific exposure and test negative within the first few weeks, your doctor will likely recommend retesting later to rule out an infection that hadn’t become detectable yet.
For hepatitis B, the viral DNA test can sometimes detect infection before the surface antigen appears in blood, making it useful in very early suspected cases. For hepatitis C, the PCR test detects the virus sooner than the antibody test does, which is why some high-risk screening protocols go straight to PCR. If you’re testing because of a known recent exposure, let your provider know the timing so they can choose the right test and schedule appropriate follow-up.