Hepatitis C Virus Antibody ( HCV ) - CLIA
The purpose of hepatitis C testing is to determine if a person has been infected by the hepatitis C virus, to evaluate a current or past infection, and to guide a patient’s treatment.
Hepatitis C is the most common form of viral hepatitis in the United States. HCV infections are classified as acute or chronic:
- Acute hepatitis C: Acute hepatitis C occurs in the first six months after a person is exposed to the virus. Early in the course of the illness, acute hepatitis C is mild and may cause no symptoms. For this reason, most people with acute hepatitis C do not know they have this infection. In about one-quarter of patients, the immune system fights off the HCV infection and the virus is cleared from the body.
- Chronic hepatitis C: If a patient’s body isn’t able to fight off the virus, they will develop chronic hepatitis C. Progression from acute to chronic hepatitis C is common, occurring in about 75% to 85% of patients. Diagnosing chronic hepatitis C as early as possible is important because prompt treatment can prevent complications linked to this condition, including liver disease, liver failure, and liver cancer.
The hepatitis C virus is found in the blood and other body fluids of a person with this infection. In the United States, the most common way of becoming infected with hepatitis C is by sharing needles used to inject drugs.
Less commonly, a person is infected with hepatitis C in other ways, including during birth, through sex with a person infected with HCV, and by coming into contact with infected blood. Currently, there is no vaccine to prevent hepatitis C.
A doctor may order hepatitis C testing for screening, diagnosis, and to guide and monitor treatment:
- Screening: Screening tests look for a disease before a person has symptoms. Because acute hepatitis C often has no symptoms, screening is an important way to diagnose hepatitis C before it causes liver damage.
- Diagnosis: When a patient has signs or symptoms of viral hepatitis, doctors use hepatitis tests to diagnose the cause of hepatitis. Hepatitis C testing can distinguish HCV from other causes of hepatitis, including hepatitis A and hepatitis B.
- Treatment: Once a patient is diagnosed, tests can determine the specific type of hepatitis C. There are several types of hepatitis C and knowing the type helps to determine the appropriate treatment. Hepatitis C testing can also measure the amount of virus in the blood. Measuring changes to the amount of HCV over time helps doctors understand if treatment is effective.
What does the test measure?
Hepatitis C testing identifies antibodies to the hepatitis C virus, detects viral RNA, and/or determines the strain of hepatitis C. Hepatitis C testing may involve several different tests:
- Hepatitis C antibody (anti-HCV) test: Antibodies are a part of the body’s response to an infection. Testing for hepatitis C antibodies determines whether or not a patient has been exposed to the hepatitis C virus at some point in their life. If this test is positive, the next step is to test for hepatitis C RNA which can tell you if you have a current infection.
- Hepatitis C RNA test: RNA is a type of genetic material from the hepatitis C virus that can be detected in the blood. If test results are positive after a hepatitis C antibody test, doctors use a hepatitis C RNA test to look for and/or measure the amount of the virus in the blood. Qualitative HCV RNA tests can detect the presence of HCV RNA, while quantitative HCV RNA tests measure the amount of HCV RNA. Understanding the amount of HCV in the blood helps to monitor the response to treatment.
- Genotype test: There are at least six types of hepatitis C, which are also called strains or genotypes. Treatment for hepatitis C depends on the strain, so genotype testing to guide treatment is performed in patients who are diagnosed with an HCV infection.
When should I get hepatitis C testing?
When used for early detection in patients without symptoms of hepatitis C, screening is recommended at least once for all adults aged 18 years or older, except in locations with a very low prevalence of HCV. Screening is also recommended during pregnancy and for patients of any age with risk factors for HCV infection. In patients with risk factors, periodic screening is recommended for as long as risk factors persist.
Risk factors for HCV include:
- Current or past injectable drug use
- Having a blood transfusion or organ transplant before July 1992
- Receiving kidney dialysis
- Having contact with needles, including at work and while getting tattoos or piercings
- Working or living in a prison
- Being born to a mother with hepatitis C
- Having an HIV infection
- Engaging in unprotected sex
Hepatitis C testing may be recommended for patients with symptoms of hepatitis or known exposure to hepatitis C. If a patient develops symptoms of hepatitis without known exposure to HCV, doctors typically order an acute viral hepatitis panel that looks for evidence of hepatitis A, B, and C in one sample of blood.
Although hepatitis C often causes no symptoms, patients may develop symptoms within one to three months after contracting the virus. Symptoms may include:
- Dark yellow urine
- Fatigue or tiredness
- Clay- or gray-colored stools
- Pain in the abdomen or joints
- Nausea, vomiting, or loss of appetite
- Jaundice or yellowish skin and eyes
Hepatitis C testing may also be performed when liver tests are abnormal or when diagnosing the cause of existing liver damage.