There are a few different tests that can diagnose Hepatitis C (or say for sure that a person has the disease). These tests are called HCV antibody, ELISA, Western blot, and quantitative HCV RNA tests. A technique called polymerase chain reaction (PCR) can show that a person has Hepatitis C virus RNA (part of the virus's genetic blueprint) one to two weeks after the person becomes infected. Tests that look for Hepatitis C antibodies (which the body makes to fight the disease) cannot be done this quickly after infection, because the antibodies can take much longer to form and show up.
A person has chronic Hepatitis C if he has been infected with the Hepatitis C virus for more than six months. Because people with chronic Hepatitis C often have no symptoms for decades, doctors often diagnose it through liver function tests (which test how well the liver is working) or by doing routine (regular) screening of high-risk people. Tests cannot tell whether an infection is acute or chronic.
Hepatitis C testing usually begins with blood tests that look for antibodies to the Hepatitis C virus, using a technique called an enzyme immunoassay. If this test is positive (showing that the body is making antibodies to fight the Hepatitis C virus), the person will be tested a second time to make sure that the results are correct and to see how serious the infection is. The results are confirmed using a technique called a recombinant immunoblot assay, and an HCV RNA polymerase chain reaction shows how serious the infection is. If the immunoblot is positive, but there are no Hepatitis C virus RNA, this shows that the person had an infection, but it cleared up either with treatment or on its own. If the immunoblot is negative, this shows that the immunoassay (the first test) was wrong, and the person does not have Hepatitis C. It takes six to eight weeks after a person gets infected before the immunoassay will test positive.
During the first part of a Hepatitis C infection, a person's liver enzymes may change; on average, they begin to rise seven weeks after infection. A person's liver enzymes usually do not affect how severe their infection is.
A test called a liver biopsy can show whether a person's liver has been damaged, or how badly it has been damaged, by Hepatitis C. However, there are some risks from the procedure. In a biopsy, a doctor takes a small piece out of the patient's liver so that he can test it. There are three major changes to the liver that a biopsy usually shows. One is that lymphocytes (a type of white blood cell) show up in the liver tissue. Another is that lymphoid follicles (small masses or swellings) show up in the portal triad, a part of the liver. The third is changes to the bile ducts (these carry bile, which is made in the liver and is needed to help a person digest their food, to other parts of the body). Many blood tests are available which try to measure how much damage there is to a patient's liver, in order to avoid the need for a biopsy and its risks.
As few as 5–50% of infected people in the United States and Canada (or 5 to 50 out of every 100) know that they have Hepatitis C. Doctors suggest that people who are at high risk for the disease, including people with tattoos, should get tested. Screening is also suggested for people with elevated (high) liver enzymes, since this is often the only sign that a person has chronic hepatitis. Routine screening (testing everyone) is not recommended in the United States.
As of 2012, there is no vaccine that works to prevent Hepatitis C. Researchers are working on vaccines, are some are making progress. The spread of Hepatitis C can be prevented by using a combination of strategies, like needle exchange programs (where IV drug users can get clean needles which will not spread the virus) and treatment for drug abuse. If these strategies are used together, the risk of IV drug users getting Hepatitis C drops by about 75%. At a national level - within each country - screening blood donors is important for preventing the spread of Hepatitis C. So is using universal precautions in healthcare facilities. (This means that healthcare workers treat every patient as if he has Hepatitis C, and they always wear gloves, clean their equipment properly, and keep things sterile so that diseases cannot be spread.) In countries that do not have enough sterile syringes to use a new needle for every patient, healthcare providers should give medications orally (by mouth) rather than via injection (using a needle) so that needles do not have to be re-used.
The Hepatitis C virus causes chronic infection in 50–80% of infected persons (or 5 to 8 out of every 10). About 40-80% of these cases (or 4 to 8 out of 10) clear up with treatment. Although this almost never happens, chronic Hepatitis C can sometimes clear up on its own, without treatment. Doctors suggest that people with chronic Hepatitis C should avoid drinking alcohol and taking medications that can be toxic (or poisonous) to the liver. They also suggest that people with chronic infections should be given vaccines for Hepatitis A and Hepatitis B. People with cirrhosis should also have ultrasound tests for liver cancer.
If a person has liver abnormalities (changes in the liver that are not normal) due to Hepatitis C virus infection, the person should get treatment. The first treatment that is used is a drug called pegylated interferon given together with the antiviral (virus-killing) drug ribavirin. These medications are given for 24 or 48 weeks, depending on what type of Hepatitis C virus the person has. About 50–60% of people who are treated improve. For people with Hepatitis C virus genotype 1, treatment may work even better if another medication - either boceprevir or telaprevir - is given along with ribavirin and peginterferon alfa. Side effects with treatment are common; half of people treated get flu-like symptoms, and a third have emotional problems. Treatment works better if it is given during the first six months than after Hepatitis C becomes chronic. If a person gets a new infection and it has not cleared up after eight to twelve weeks, doctors usually suggest giving pegylated interferon for another 24 weeks. For people with thalassemia (a blood disorder), ribavirin appears to be a helpful treatment, but it makes it more likely for patients to need blood transfusions (where they need to be given blood from another person).
Some supporters of alternative medicine say that alternative therapies like milk thistle, ginseng, and colloidal silver can be helpful for Hepatitis C. However, there is no proof that any alternative therapy has any effect on the Hepatitis C virus.
People respond differently to treatment, depending on which of the Hepatitis C virus genotypes they have. About 40-50% in people with genotype 1 have a good, stable response with 8–48 weeks of treatment. In people with genotypes 2 and 3, about 70-80% have a good, stable response with 24 weeks of treatment. About 65% of people with genotype 4 have a good, stable response with 48 weeks of treatment. There is not much evidence about how well treatment works for people with genotype 6 disease is currently sparse. The evidence that does exist looks at results after 48 weeks of treatment at the same medication doses as people with genotype 1.
Between 130 and 170 million people, or about 3% of all of the people in the world, are living with chronic Hepatitis C. Between 3–4 million people get infected per year. More than 350,000 people die every year from diseases caused by Hepatitis C. The numbers of people getting Hepatitis C have increased a lot in the 20th century for a few different reasons. More people are using IV drugs. Also, more people are getting medical care with medical equipment that is not sterile, and it is more common for medications to be given intravenously.