To screen for and diagnose a hepatitis C virus (HCV) infection; to guide and monitor treatment of the infection
Hepatitis C Testing
For screening: at least once when you are age 18 years or older; when you are pregnant (with each pregnancy); when you have risk factors for HCV infection, regardless of age
A blood sample drawn from a vein
Hepatitis C (HCV) is a virus that causes an infection of the liver that is marked by liver inflammation and damage. Hepatitis C tests are a group of tests that are performed to diagnose hepatitis C infection and to guide and monitor treatment of the infection.
Hepatitis C tests include:
- HCV antibody test—detects antibodies in your blood that are produced in response to an HCV infection
- HCV RNA test—detects and measures viral hepatitis C RNA in the blood
- HCV genotype test—determines the specific subtype of the virus; this information is useful in guiding treatment.
Hepatitis C is one of five viruses identified so far, including A, B, D, and E, that are known to cause hepatitis.
HCV is spread when contaminated blood enters the body, primarily though sharing needles and syringes during IV drug use. HCV is spread less commonly by sharing personal items contaminated with blood (e.g., razors, toothbrushes), through sex with an infected person, needlestick injuries to healthcare workers, unregulated tattooing, and from mother to baby during pregnancy and childbirth. Before tests for HCV became available in the 1990s, HCV was often transmitted by blood transfusions. Currently, there is no vaccine to prevent hepatitis C.
- Acute hepatitis C—for some people, infection with HCV is a short-term illness, usually with few, mild symptoms or no symptoms, and the virus is cleared from the body without specific treatment. Occasionally (about 20 to 30% of the time), this acute stage of infection can cause more severe symptoms, particularly jaundice and fatigue.
- Chronic hepatitis C—more than half of people infected develop chronic hepatitis C that, without treatment, can lead to serious, long-term health problems like cirrhosis and liver cancer, and may be fatal. Chronic hepatitis progresses slowly over time, so infected individuals may not be aware they have the condition until it causes enough liver damage to affect liver function.
The Centers for Disease Control and Prevention (CDC) estimates that there were approximately 44,700 cases of acute hepatitis C in the U.S. in 2017 and that there are 2.4 million people in the U.S. living with chronic hepatitis C. Many of these people don't know they are infected. The only way to know is to get tested for hepatitis C.
If you are diagnosed with hepatitis C, your healthcare practitioner may recommend an antiviral treatment to cure your infection or refer you to a healthcare practitioner who specializes in treating liver diseases or infectious diseases. The HCV RNA test may be repeated prior to starting treatment to determine whether the virus is still present and your infection persists, and also to provide a baseline to compare to during treatment.
There are several antiviral treatments available to treat hepatitis C. While some treat specific types (genotypes) of the virus, there are some that treat all genotypes. Treatment typically involves taking medication by mouth (oral) for about 8 to 12 weeks, although it can be longer in some cases. These medications can cure over 90% of people with chronic hepatitis C with relatively few side effects. Your infection is considered cured if you have no detectable HCV in your blood 12 weeks after completing treatment.
- How is the test used?
The various hepatitis C tests have different uses:
An HCV antibody test is used to screen for past exposure and current infection. It detects the presence of antibodies to the virus in your blood that are produced by the immune system in response to infection. This test cannot distinguish whether you have an active or a previous HCV infection. There is some evidence that if your test is "weakly positive," it may be a false positive. The CDC recommends that all positive antibody tests be followed by an HCV RNA test (see below) to determine whether or not you have an active infection.
The HCV antibody test may be performed as part of an acute viral hepatitis panel to determine which of the most common hepatitis viruses is causing your symptoms.
HCV RNA test, Quantitative (HCV viral load) detects and measures the amount of viral RNA in your blood. This test may be used:
- In follow up to a positive HCV antibody test to confirm the presence of the virus and diagnose an active infection
- As an initial test for early, acute HCV infection or as follow-up to a negative antibody test if recent exposure is strongly suspected; this is because HCV antibodies may not develop for two months after exposure.
- To help determine your response to therapy by comparing the amount of virus before, during, and after treatment
- HCV RNA, Qualitative test is used to distinguish between a current or past infection. It is reported as a "positive" or "detected" if any HCV viral RNA is found. Otherwise, the report will be "negative" or "not detected." This test is not often used anymore.
- Hepatitis C virus genotype is used to determine the kind, or genotype, of the HCV you have to help guide treatment. There are 6 major types of HCV and more than 50 subtypes identified. The most common, genotype 1, accounts for about 75% of cases in the U.S. The drugs selected for your treatment depend in part on the genotype of HCV causing your infection.
- An HCV antibody test is used to screen for past exposure and current infection. It detects the presence of antibodies to the virus in your blood that are produced by the immune system in response to infection. This test cannot distinguish whether you have an active or a previous HCV infection. There is some evidence that if your test is "weakly positive," it may be a false positive. The CDC recommends that all positive antibody tests be followed by an HCV RNA test (see below) to determine whether or not you have an active infection.
- When is it ordered?
The CDC, the Infectious Diseases Society of America (IDSA), the American Association of the Study of Liver Diseases (AASLD), and the U.S. Preventive Services Task Force (USPSTF) recommend screening with an HCV antibody test at least once in your lifetime when you are 18 years old or older (until age 79, says the USPSTF). The CDC also recommends HCV screening for women with each pregnancy or for anyone who requests it.
One-time screening is recommended regardless of age if you:
- Have ever injected illegal drugs
- Received a blood transfusion or organ transplant before July 1992*
- Have received clotting factor concentrates produced before 1987
- Were ever on long-term dialysis
- Are a child born to HCV-positive women
- Have been exposed to the blood of someone with hepatitis C
- Are a healthcare, emergency medicine, or public safety worker who had needlesticks, sharps, or mucosal exposure to HCV-positive blood
- Have evidence of chronic liver disease
- Have HIVabout 21% of those with HIV are also infected with HCV (co-infection).
*The blood supply has been monitored in the U.S. since 1992, and any units of blood that test positive for HCV are rejected for use in another person. The current risk of HCV infection from transfused blood is about one case per two million transfused units.
Screening at regular intervals is recommended if you have ongoing risk of HCV infection, such as current injection drug use and sharing needles or syringes.
HCV antibody testing may be done when you have abnormal results on a liver panel or signs and symptoms associated with hepatitis and/or liver damage. In these cases, it may be done as part of an acute hepatitis panel. Most people newly infected with HCV have no symptoms or symptoms that are so mild that they rarely prompt a visit to a healthcare provider to get tested for HCV. However, about 10-20% of people may experience signs and symptoms such as:
- Abdominal pain
- Loss of appetite, nausea, vomiting
- Dark urine
- Light-colored stools
- Yellowing of eyes and skin (jaundice)
An HCV RNA test (viral load) is ordered when:
- You have a positive HCV antibody test to confirm an active infection; some laboratories will automatically perform this test if the HCV antibody test is positive.
- There is strong suspicion that you have an early HCV infection or were exposed recently (e.g., within the last two months), regardless of HCV antibody results
- You are treated for chronic hepatitis C, at the start of treatment and periodically to monitor your response, and about 12 weeks after finishing treatment to ensure the infection is cured
HCV genotype testing is done when you have been diagnosed with a chronic HCV infection and will begin treatment.
- What does the test result mean?
Screening and diagnosis
An HCV antibody test is typically reported as "positive" or "negative."
Results of HCV viral load testing are reported as a number of virus copies present. If no virus is present or if the amount of virus is too low to detect, the result is often reported as "negative" or "not detected."
Interpretation of the HCV screening and follow-up tests is shown in the table below.
- In general, if your HCV antibody test is positive, then you have likely been infected at some time with hepatitis C.
- If the laboratory reports results as weakly positive, most of these results are false positive and some laboratories will retest your sample with another test before reporting it as positive.
- If your HCV RNA test is positive, then you have a current infection.
- If no HCV viral RNA is detected, then you either do not have an active infection or the virus is present in very low numbers.
HCV Antibody HCV RNA Interpretation Negative No infection or it is too soon after exposure and HCV antibody has not yet developed; if suspicion remains high, an HCV RNA test is done. Negative Positive Early, acute HCV infection Positive or weakly positive Negative Past infection or no infection (false-positive screen, most are weakly positive) Positive Positive Current, active infection
Guiding and monitoring treatment
The result of your HCV genotype test identifies which strain of HCV you have and helps guide the selection and the length of your treatment. Treatments may differ depending on a variety of factors, including HCV genotype and the health of your liver.
An HCV viral load (HCV RNA quantitative) can indicate whether or not treatment is effective.
- A high or increasing viral load may mean that treatment is not working.
- A low, decreasing, or undetectable viral load likely means that the treatment is working.
Successful treatment usually leads to undetectable viral load after treatment is completed. According to guidelines from the AASLD and the IDSA, an undetectable viral load in your blood 12 weeks after the end of the treatment means that your HCV infection has responded to therapy.
- If the disease is very mild, why should I be tested?
Hepatitis C often leads to chronic hepatitis, which can progress to cirrhosis and liver cancer (hepatocellular carcinoma). Early detection of the virus can alert your healthcare provider to follow your liver function more closely than usual and to treat you if you are chronically infected.
- Besides HCV testing, what other tests might be done?
Healthcare practitioners may also order a liver panel, which is a group of tests that help assess the health of your liver. Liver tests such as ALT and AST may be used to detect ongoing liver injury. You will likely be checked to see if you are immune to hepatitis A and hepatitis B, and if not, you will be offered vaccination, since infection with these other viruses can further damage your liver. Other tests such as albumin, prothrombin time, and bilirubin can also be used. They are typically normal unless you have developed cirrhosis. Sometimes a liver biopsy may be performed to determine the severity of liver damage. If you are going to be treated, you will be checked for exposure or infection with hepatitis B virus, as HCV treatment can cause a flare-up of hepatitis B.
- Can I be vaccinated against HCV?
No. Currently, there is no vaccine available. Although research is ongoing to develop one, most attempts to develop a vaccine have so far been unsuccessful in protecting people.
- Once I have been treated and/or recovered from hepatitis C, can I get infected again?
Yes. A prior infection with HCV does not protect you from another infection—it does not make you immune to HCV. Most people do not have an effective immune response to the virus. Changes that the virus undergoes as it replicates during an infection make it difficult for the body to fight against the initial or subsequent infections.
- What is the treatment for HCV?
There are several drugs that can be used to treat HCV infection. Most commonly, a combination of drugs is used, and new drugs are under development. Before 2000, chronic HCV was curable in only 10% of cases. Now, treatments for HCV can cure over 90% of people with hepatitis C before late complications occur, but even those with advanced liver disease often respond to treatment. This increases the opportunity to intervene early and prevent HCV-associated deaths.
- According to the CDC, recent treatment guidelines recommend monitoring people with acute HCV but only considering treatment if the infection persists longer than 6 months.
- Chronic HCV is usually treated with a combination of drugs.
- Can I test myself for HCV at home?
There is an FDA-approved test kit available for collecting samples to send to a laboratory for testing. Confidential test results are provided over the telephone. You cannot actually perform the test yourself at home.
- Can this test be done at my healthcare practitioner’s office?
Maybe. There are rapid HCV antibody tests available that can be done at the point of care (POC), in settings such as your healthcare practitioner’s office, community health clinics, and emergency rooms. They provide results in about 20 minutes. However, a positive result requires confirmation of active disease with an HCV RNA test, which is performed in a laboratory.
- How can I tell if I am contagious and can spread the infection to others?
If you have detectable HCV RNA in your blood, you have the potential to spread the disease to other people. Hepatitis C is spread by exposure to contaminated blood. The most common mechanism of exposure is the sharing of needles or other 'works' used in consuming drugs such as cocaine or heroin. Other routes of transmission include use of contaminated equipment for body piercing and tattooing, occupational exposure of healthcare workers to used needles or other sharp objects, and, less commonly, through sexual activity that results in tissue tears or from mother to baby during childbirth.