Infection Tests

Hepatitis C Antibody

Also written as: Anti-HCV, HCV Ab, Hepatitis C screen

Screens for exposure to hepatitis C; a positive result is followed by an RNA test for current infection.

What it measures

Antibodies the immune system has made against the hepatitis C virus. It detects that the body has encountered the virus at some point, not whether the virus is still present.

Why a doctor orders it

Ordered as a one-time screen recommended for most adults, and when liver tests are abnormal or a past exposure is possible. It is the standard first step because it is a simple blood test with good sensitivity for prior exposure.

What is generally associated with a higher result

In general terms, a positive antibody generally means exposure to hepatitis C at some point. It does not distinguish a current infection from one that cleared naturally or after treatment, because the antibody usually stays positive for life. For that reason a positive antibody is routinely followed by an RNA test, which looks for the virus itself and shows whether infection is active now.

What is generally associated with a lower result

A negative antibody is generally read as no evidence of past or current infection, with the caveat that antibodies take weeks to months to appear after a new exposure.

Everyday things that move this number

Not every shift in a value reflects disease. These are ordinary factors known to affect this particular measurement:

• The window period after a recent exposure, before antibodies have developed
• A past infection that cleared, which can leave the antibody positive for life
• Occasional false positives, which is one reason confirmatory RNA testing is standard practice
• High-dose biotin supplements, which can interfere with some antibody assays
• Lab method differences between screening platforms

Questions to take to your appointment

• Has an RNA (viral load) test been done to check whether the infection is current?
• If the RNA test comes back negative, what does a lasting positive antibody mean going forward?
• Should my liver enzymes be checked alongside this?
• Is the timing right, or was this drawn too soon after a possible exposure?

Build a printable questionnaire with your own results →

Where to read more

MedlinePlus, from the US National Library of Medicine, publishes patient-facing pages on individual lab tests and is a reliable next stop: medlineplus.gov/lab-tests .

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