You can be infected with the hepatitis C virus (HCV) and have no symptoms. Your doctor could find it when they check your blood and see that your level of certain liver enzymes is high. If that happens, they'll follow up with other tests to confirm you have the disease.
Who Should Get Tested for Hepatitis C?
The CDC recommends that you get tested at least once no matter what. Definitely get screened if any of these things apply to you:
- You were born between 1945 and 1965.
- You use or inject drugs.
- You have ever injected drugs -- even if it was just once or a long time ago.
- You have HIV.
- You’re on kidney dialysis.
- You have abnormal alanine aminotransferase levels (ALT).
- You had a blood transfusion, blood components, or an organ transplant before July 1992.
- You’ve ever gotten clotting factor concentrates made before 1987.
- You received blood from a donor who later tested positive for hepatitis C virus.
- You’re a health care worker, first responder, or have another job that exposes you to HCV-infected needles.
- You were born to a mother with HCV.
Why Should You Get Tested?
Hepatitis C Testing and Diagnosis
Doctors will start by checking your blood for:
Anti-HCV antibodies: This blood test is the first -- and sometimes only -- one you may get. Also called the ELISA screen, it checks for antibodies that your body releases to fight the virus. These are proteins your body makes when it finds the hep C virus in your blood. They usually show up about 12 weeks after infection. Your test will be either negative or positive for antibodies. It usually takes a few days to a week to get results, though a rapid test is available in some places.
What the results mean
Negative (non reactive). This is when your blood shows no signs of HCV antibodies. Most of the time, that’s because you never came in contact with the virus and you do not have hep C.
Sometimes, your negative result can be false, meaning you have HCV. That may happen if you:
- Took the test too soon after your exposure. This test checks for only HCV antibodies, which can take several months to appear.
- Have HIV, a donated organ, or other conditions that weaken your immune system, which can suppress your antibodies
- Get hemodialysis for kidney problems
If you’ve been exposed in the last 6 months, you’ll need to be retested.
Positive (reactive). This means you’ve been infected with HCV. But false positives are surprisingly common. More than 1 in 5 people who test positive don’t actually have hepatitis C. Possible reasons include:
- In as many as 1 in 4 people, the HCV goes away without treatment. But even after this “natural clearance,” the HCV antibodies will always be in your blood.
- The test may mistake HCV antibodies for those for lupus, rheumatoid arthritis, and other conditions.
- Babies born to mothers with hep C probably have HCV antibodies. But most newborns aren’t actually infected.
No test is foolproof. False positive errors happen more often in groups of people -- like medical workers stuck with tainted needles -- who have low odds of having HCV.
If your antibody test is positive, you’ll need to have a different kind of test:
RNA: This test measures the number of viral RNA (genetic material from the hepatitis virus) particles in your blood, also called the “viral load.” The RNA test is almost 100% accurate and can detect an infection within a couple of weeks after exposure.
What the results mean
Negative: Even if you tested positive for antibodies, a negative result on this test means the earlier result was probably not true. For example, you may have had an infection that went away on its own. False negatives with RNA tests are very unlikely, but possible. You could still have super low numbers of the virus in your blood.
If you have HIV or other things that raise your chances for HCV, you might want to get another RNA test later. You can also get a different kind of RNA test, called a “qualitative” test. This checks simply if your blood has any HCV. But it can be more accurate than the viral load test because it can detect even very low amounts of the virus.
Positive: You have an active HCV infection. Your doctor will talk to you about treatment. You might get more RNA tests to monitor your disease.
Because RNA tests are so sensitive, false positives can sometimes happen. That’s usually because the sample has been contaminated. Like false negatives, this is very rare.
Tests After the Diagnosis
Once the doctor knows you have hep C, they’ll do tests to find out more about your condition. This will help determine your treatment. They could include:
- Genotype tests to find out which of the six kinds (genotypes) of hepatitis C you have.
- Liver function tests. They measure proteins and enzymes levels, which usually rise 7 to 8 weeks after you’re infected. As your liver gets damaged, enzymes leak into your bloodstream. But you can have normal enzyme levels and still have hepatitis C.
- Tests to check for liver damage. You might get:
- Elastography. Doctors use a special ultrasound machine to feel how stiff your liver is.
- Liver biopsy. The doctor inserts a needle into your liver to take a tiny piece to examine in the lab.
- Imaging tests. These use various methods to take pictures or show images of your insides. They include:
- CT scan
- Magnetic resonance imaging (MRI)
- Magnetic resonance elastography (MRE)