Hepatitis C Virus Antibodies
If you may have been exposed to/have risk factors for the hepatitis C virus, such as through contact with infected blood, sexual relations with an person known to be infected person, if you have ever injected drugs or you have symptoms associated with viral liver disease
A blood sample taken from a vein in your arm
No test preparation is needed
Hepatitis C is a virus that can infect and damage the liver. In most cases, it is contracted through exposure to blood (usually from sharing contaminated needles while injecting drugs or, before 1992, through a blood transfusion or, through sex with an infected person. Healthcare workers can be exposed to the virus through their work and it can also be passed from mother to baby.
Many people who are infected with Hepatitis C are not aware that they are carrying the virus. Most people do not have any symptoms when they are first infected or their symptoms are mild and non-specific . However Hepatitis C virus does not go away and you can have a chronic (longstanding) infection without showing any signs of it. This can go on for a number of years (even decades) but if untreated it can eventually cause significant liver damage. About 65-75% of those infected can develop chronic liver disease with 20-30% of these developing cirrhosis over many years.
Hepatitis C antibody is produced by the body in response to exposure to the hepatitis C virus (HCV). The most common test for HCV looks for these antibodies in your blood. Some first line tests are also looking for the hepatitis C antigen, which the virus itself produces, as well as your antibody response. Other tests detect the presence of and actual amount of virus present or determine the specific subtype of virus.
How is it used?
Each of the most common tests have a slightly different purpose:
- Anti-HCV Antibody test detect the presence of antibodies to the virus. These are substances produced by the body when it encounters the virus , so a positive results shows that you have been exposed to HCV. These tests on their own may not be able to tell if you still have an active viral infection, only that you were exposed to the virus in the past. Usually, the test is reported as “positive” or “negative.” There is some evidence that, if your test is “weakly positive,” it may not mean that you have been exposed to the HCV virus. All positive results (weak or strong) will either be repeated using a second antibody test or most likely using the test for the virus genetic material , the viral load test (described below).
- Viral Load or Quantitative HCV tests measure the number of viral particles in your blood. Viral load tests are used before treatment to help determine how long treatment needs to be given (along with other factors, such as your age, gender, the changes seen in a liver biopsy, and genotype, discussed below). It is also used to follow response to treatment by comparing the amount of virus before, during and after treatment at time points dependant on what type and length of treatment is given. The aim is to get the levels of virus to undetectable/not detected.
- Viral genotyping is used to determine the genotype (‘strain’), of the virus present. There are 6 major types of HCV. Genotypes 1, 2 and 3 are found across the world and genotype 1 is the most common. It can be important to know the virus genotype to help doctors decide on the treatment plan. The antiviral drugs which are now used are called direct acting antivirals (DAAs) and they are effective against all genotypes of HCV and this treatment is successful in 90% of patients .
When is it requested?
Hepatitis C infection is a common cause of chronic liver disease . About 65-75% of those infected will develop chronic hepatitis, and about 20-30% of those develop cirrhosis. HCV testing is recommended in the following cases:
- If you have ever injected illegal drugs
- If you received a blood transfusion or organ transplantation before mid-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 UK since mid-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 less than 1 case per million transfused units.
A positive anti-HCV test will be confirmed with an alternative test, especially if the test is “weakly positive.” HCV viral load and genotyping will be performed to plan treatment and to monitor response to treatment.
What does the test result mean?
If the antibody test result is positive, you have probably been infected with hepatitis C, even if it was so mild you did not realise you had it.
A repeat antibody test will usually be requested, followed by a viral load test.
A positive (or detectable) HCV RNA means that you are currently infected by HCV.
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.
Is there anything else I should know?
If the disease is very mild, why should I be tested?
Are there other tests used to follow the disease?
Yes. Liver function tests, such as ALT and AST, are used to assess liver injury. Persons who are still infected with HCV but always have normal AST and ALT probably have very mild liver disease and may not need treatment. Other liver tests, such as albumin, prothrombin time, and bilirubin can also be used; they are typically normal unless the person has developed cirrhosis. However, in severe liver damage/cirrhosis, liver function tests can be normal. Sometimes a liver biopsy may be performed to determine how severe the liver damage is.
Can I be vaccinated against HCV?
Is there treatment for HCV?
Yes, there are currently a good range of available treatments for HCV infection. Most patients will be given Direct Acting Antiviral treatment. This will usually be a combination of two or more different drugs. They are given as tablets and the course of treatment is 8-12 weeks. 90% of patients clear the HCV virus using these DAA treatments.
Can I test myself for the virus at home?
How can I tell if I can spread the infection to others?
If a person has detectable HCV RNA in their blood, they have the potential to spread the disease to other people. The likelihood of giving your sexual partner HCV is relatively low, even if you have the virus in your blood however most doctors would recommend safe sex (such as using condoms), especially if you have more than one sexual partner. Pregnant women who have the HCV virus in their blood have about a 5% chance of spreading the infection to their infant. HCV is highly infectious if needles or (perhaps) razors are shared by an infected and an uninfected person. HCV cannot be spread by casual contact, even if you live in the same house with an infected person.