Hepatitis C Test
Hepatitis C Test in Shanghai
Hepatitis C Fact
What is hepatitis C?
Hepatitis C is a disease caused by a virus that infects the liver. In time, it can lead to permanent liver damage as well as cirrhosis, liver cancer, and liver failure.
Many people do not know that they have hepatitis C until they already have some liver damage. This can take many years. Some people who get hepatitis C have it for a short time and then get better. This is called acute hepatitis C. But most people who are infected with the virus go on to develop long-term, or chronic, hepatitis C.
Although hepatitis C can be very serious, most people can manage the disease and lead active, full lives.
What causes hepatitis C infection?
Hepatitis C is caused by the hepatitis C virus. It is spread by contact with an infected person's blood.
You can get hepatitis C if: You share needles and other equipment used to inject illegal drugs. This is the most common way to get hepatitis C in the United States. You had a blood transfusion or organ transplant before 1992. As of 1992 in the United States, all donated blood and organs are screened for hepatitis C. You get a shot with a needle that has infected blood on it. This happens in some developing countries where they use needles more than once when giving shots. You get a tattoo or a piercing with a needle that has infected blood on it. This can happen if equipment isn't cleaned properly after it is used.
In rare cases, a mother with hepatitis C spreads the virus to her baby at birth, or a health care worker is accidentally exposed to blood that is infected with hepatitis C.
Experts are not sure if you can get hepatitis C through sexual contact. If there is a risk of getting the virus through sexual contact, it is very small. The risk is higher if your sex partner has hepatitis C or if you have many sex partners.
You cannot get hepatitis C from casual contact such as hugging, kissing, sneezing, coughing, or sharing food or drink.
What are the symptoms?
Most people have no symptoms when they are first infected with the hepatitis C virus. If you do develop symptoms, they may include: Feeling very tired. Joint pain. Belly pain. Itchy skin. Sore muscles. Dark urine. Yellowish eyes and skin (jaundice). Jaundice usually appears only after other symptoms have started to go away.
Most people go on to develop chronic hepatitis C but still do not have symptoms. This makes it common for people to have hepatitis C for 15 years or longer before it is diagnosed.
How is hepatitis C diagnosed?
Many people find out by accident that they have the virus. They find out when their blood is tested before a blood donation or as part of a routine checkup. Often people with hepatitis C have high levels of liver enzymes in their blood.
If your doctor thinks you may have hepatitis C, he or she will talk to you about having a blood test. If the test shows hepatitis C antibodies, you have had hepatitis C at some point. A second test can tell if you have hepatitis C now.
When blood tests show that you have hepatitis C, you may need a liver biopsy to see if the virus has caused scarring in your liver. During a liver biopsy, a doctor will insert a needle between your ribs to collect a small sample of liver tissue to look at under a microscope. See a picture of the placement of the needle for a liver biopsy.
Some people prefer to find out on their own if they have been exposed to hepatitis C. You can buy a home test called a Home Access Hepatitis C Check kit at most drugstores. If the test shows that you have been exposed to the virus in the past, be sure to talk to your doctor to find out if you have the virus now.
How is it treated?
You and your doctor need to decide if you should take antiviral medicine to treat hepatitis C. It may not be right for everyone. If your liver damage is mild, you may not need medicine.
If you do take medicine, the best treatment is a combination of two medicines that fight infection: peginterferon and ribavirin. How well these medicines work depends on how damaged your liver is, how much virus you have in your liver, and what type of hepatitis C you have.
Taking care of yourself is an important part of the treatment for hepatitis C. Some people with hepatitis C do not notice a change in the way they feel. Others feel tired, sick, or depressed. You may feel better if you exercise and eat healthy foods. To help prevent further liver damage, avoid alcohol and illegal drugs and certain medicines that can be hard on your liver.
At a Glance Why Get Tested?
To screen for and diagnose a hepatitis C virus (HCV) infection and to monitor treatment of the infection
When to Get Tested?
When you may have been exposed to the hepatitis C virus, such as through contact with infected blood, have symptoms associated with liver disease, or have risk factors for hepatitis C infection
Sample Required?
A blood sample drawn from a vein in your arm
Test Preparation Needed?
None
Test Sample
The Test Sample What is being tested?
Hepatitis C (HCV) is a virus that causes an infection of the liver that is characterized by liver inflammation and damage. It is one of five "hepatitis viruses" identified so far, including A, B, D, and E, that are known to cause the disease. HCV is spread by exposure to contaminated blood, primarily though the sharing of needles by intravenous drug users, but also by sharing personal items contaminated by blood such as razors, through sex with an infected person, via health care occupational exposure, and from mother to baby during childbirth. Before tests for HCV became available in the 1990s, HCV was often transmitted by blood transfusions. While HCV is not as contagious as Hepatitis B, there is currently no vaccine to prevent infection. Hepatitis C infection is a common cause of chronic liver disease in North America; about 2% of all adults in the United States have been exposed to the virus, and up to 85% of those who have it will become chronically infected after their acute infection resolves.
According to the CDC, an estimated 3.2 million people in the U.S. have a chronic HCV infection. Many of those who are infected have no symptoms and are not aware of the condition. The acute HCV infection may cause few to mild nonspecific symptoms, and the chronic infection may simmer quietly for a decade or two before causing sufficient liver damage to affect liver function.
Hepatitis C infections cause increased risk of developing some other serious conditions:
- About 60-70% of those infected will develop chronic liver disease.
- About 20-30% will develop cirrhosis over 20 years; recent projections suggest that almost 45% will eventually develop cirrhosis.
- HCV can cause death in about 1-5% of those infected.
Hepatitis C tests are a group of tests that are performed to detect, diagnose, and monitor the treatment of a hepatitis C viral infection. The most common test for HCV looks for antibodies in your blood that are produced in response to an HCV infection. Other tests detect the presence of viral RNA, the amount of viral RNA present, or determine the specific subtype of the virus.
How is the sample collected for testing?
A blood sample is taken by needle from a vein in the arm.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
The Test
How is it used?
Hepatitis C tests are used to detect and diagnose an infection and/or to monitor the treatment of hepatitis C virus (HCV). Tests are used to detect the condition if a person:
- Has been exposed to someone with HCV
- Participates in high risk behaviors such as injecting street drugs
- Has abnormal liver function tests
- Has symptoms associated with liver disease, such as jaundice, dark urine, nausea, or unexpected weight gain or loss
The following tests may be used to screen for and/or detect HCV:
- Anti-HCV test detects the presence of antibodies to the virus, indicating exposure to HCV. This test cannot distinguish between someone with an active or a previous HCV infection. Usually, the test is reported as "positive" or "negative." There is some evidence that if the test is "weakly positive," it may be a false positive. The Centers for Disease Control and Prevention (CDC) suggests that weakly positive tests be confirmed with the HCV RIBA test before being reported.
- HCV recombinant immunoblot assay (RIBA) test is an additional test ordered to confirm the presence of HCV antibodies. In most cases, it can tell if the positive anti-HCV test was due to exposure to HCV (positive RIBA) or represents a false signal (negative RIBA). In a few cases, the results cannot answer this question (indeterminate RIBA). Like the anti-HCV test, the RIBA test cannot distinguish between a current or past infection.
The following tests may be used to diagnose a current infection and to guide and monitor treatment:
- HCV RNA test, Qualitative may be used to distinguish between a current or past infection. It is reported as a "positive" or "detected" if any HCV viral RNAis found; otherwise, the report will be "negative" or not detected." It may also be ordered after HCV treatment is complete to see if the virus has been eliminated from the blood. These tests are seldom used any more.
- HCV Viral Load (HCV RNA test, Quantitative)detects and measures the number of viral RNA particles in the blood. Viral load tests are often used before and during treatment to help determine response to treatment by comparing the amount of virus before and during treatment (usually at several time points in the first three months of treatment). Successful treatment causes a decrease of 99% or more (2 logs) in viral load soon after starting treatment (as early as 4-12 weeks) and usually leads to viral load being not detected even after treatment is completed. Some newer viral load tests can detect very low amounts of viral RNA.
- Viral genotyping is used to determine the kind, or genotype, of the HCV virus present. There are 6 major types of HCV; the most common (genotype 1) is less likely to respond to treatment than genotypes 2 or 3 and usually requires longer therapy (48 weeks versus 24 weeks for genotype 2 or 3). Genotyping is often ordered before treatment is started to give an idea of the likelihood of success and how long treatment may be needed.
When is it ordered?
The CDC recommends screening for HCV infections in the following cases:
- If you have ever injected illegal drugs
- If you received a blood transfusion or organ transplant before July 1992*
- If you have received clotting factor concentrates produced before 1987
- If you were ever on long-term dialysis
- For children born to HCV-positive women
- For health care, emergency medicine, and public safety workers after needlesticks, sharps, or mucosal exposure to HCV-positive blood
- For people with evidence of chronic liver disease
*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 1 case per two million transfused units.
Most people newly infected with HCV have no symptoms or ones that are so mild that they rarely prompt a person to visit a doctor and get tested for HCV. However, about 10-20% of people may experience symptoms such as fatigue, pain in the abdominal area, decreased appetite, and jaundice and may be tested for HCV.
A positive anti-HCV test may be confirmed with an HCV RIBA test, especially when the anti-HCV test is "weakly positive." Many physicians do not use RIBA since it still does not determine if a person is currently infected. Quantitative HCV-RNA is often ordered when the antibody test is positive to see if the infection is still present. HCV viral load and genotyping may be done when treatment is planned; viral load may be ordered periodically to monitor response to treatment and at the completion of treatment to evaluate its effectiveness.
What does the test result mean?
Interpretation of the HCV tests is shown in the table below. In general, if the HCV antibody test is strongly positive, then someone has likely been infected at some time with hepatitis C. If the HCV RNA test is positive, then the person has a current infection. If no HCV viral particles are detected, then the person either does not have an active infection or the virus is present in very low numbers.
Test results to detect, diagnose, and monitor HCV include (save to see the big picture):
An HCV viral load (HCV RNA quantitative) can indicate whether or not treatment is effective. A high or increasing viral load may be a sign that treatment is not successful whereas a low, decreasing, or undetectable viral load may imply that the treatment is working. According to the CDC, an undetectable viral load in a treated person's blood for 24 weeks after the end of the treatment means that the HCV infection has responded to therapy.
The results of the HCV genotype test identifies which type of HCV the person has and helps guide the type and often the length of treatment. There are at least six separate types (genotypes) of HCV numbered as 1 through 6 with at least an additional 50 subtypes that have been identified. Genotype 1 is the most common HCV genotype in the United States.
Is there anything else I should know?
HCV antibodies usually do not appear until several months into an infection but will always be present in the later stages of the disease.
About 25% of those with HIV/AIDS also have an HCV co-infection, and their liver disease is likely to progress at an accelerated rate.