Many people are under the impression that since their doctor has never mentioned Hepatitis C to them that they have been screened for this virus and the results were negative. Unfortunately, this couldn't be further from the truth. Currently, HCV screening is not part of a routine physical exam. In fact, unless your liver enzymes have shown up as elevated, which they will with significant liver damage, your doctor probably has not even considered Hepatitis C in relation to you. The problem with this is that by the time your liver enzymes are elevated, the Hep C virus has already made it's mark on your liver. A Hepatitis C screening test is something you need to ask for. Your doctor may even question why you want this test run. Your answer should be simple... "Because I am asking for it."
The following tests are run, in this order, when screening for Hepatitis C, confirming the diagnosis and assessing the damage the virus has done to your liver.
HCV Antibody Test: The first diagnostic test run for Hepatitis C is the antibody test. A positive test for HCV antibodies means that the person has, at one time, been exposed to the Hepatitis C virus. It can take up to 26 weeks after exposure for the antibodies to be detectable. Once a person has been exposed to the HCV virus, they will always test positive for the antibody. The antibodies are like a scar in the bloodstream. It does not, however, mean that the person has active Hepatitis C. Because up to 20% of the people who are initially infected with HCV will clear the virus on their own within six months of exposure, this test is only the beginning of the process. The next step is to find out if the virus is active. Checking for the virus in the bloodstream with a PCR test, also called a Viral Load test, does this. If exposure has been recent, (within six months) antibodies may not yet be present in the bloodstream. In this case, a PCR will confirm the presence of Hepatitis C. This test result is reported as positive or negative.
HCV Viral Load Testing: To confirm an active case of Hepatitis C, a qualitative PCR test is done to determine whether or not the HCV virus is present in a person's bloodstream. viral Load tests measure the amount of HCV RNA circulating in the bloodstream. The mere presence of detectable genetic viral material indicates that the virus is present and actively replicating. This test result is reported in numbers. Any result other than "Undetectable" is a positive result. The lower this number is, the better chance a person has of responding to treatment. HCV Viral Load testing is also done at specific times during the treatment process to determine if and how well the treatment is working. This test has two purposes, to detect an active HCV infection and to measure treatment response. There is no correlation at all between this number and the amount of liver damage one has or the progression of the disease process. The results for this test often take a week or more so don't panic when you don't get the results right away. The reason it can take so long is that the labs usually only run this test once a week.
HCV Genotype Testing: The Genotype refers to the genetic structure of the Hepatitis C virus. There are more than six different genotypes, which are numbered in the order of their discovery. Each Genotype has subtypes, that are lettered. Genotype testing determines which of the HCV virus(s) an individual carries. The Genotype determines the type of treatment needed, the length of treatment and dosages of medications as well as how difficult it may be to clear the virus. Worldwide, HCV Genotype 1 is the most common. In the U.S., 75% of all infections are Genotype 1. It is possible to be infected with more than one HCV Genotype. This test result will be reported as a number, followed by a letter.
Liver Biopsy: Unfortunately, liver function tests do not tell the entire story about the health of the liver. Measuring the HCV viral load and liver enzyme levels in the blood cannot determine if, or how much, damage has been done to the liver. A liver biopsy is done to evaluate the severity of inflammation, amount of fibrosis or cirrhosis, and general health of the liver. This procedure is usually done as an outpatient at a hospital. Usually an ultrasound is done first, to determine the best placement of the needle for the biopsy. This test not only determines how healthy the liver is, but it will also help your doctor determine if and when to start treatment for Hepatitis C.
Non-Invasive Fibrosis Tests: Recently, researchers have developed non-invasive methods of determining the extent of liver damage. These are done by way of a blood test. There are blood markers that can help determine the presence of fibrosis (scarring) on the liver. The problem with these tests is that they are accurate only in determining minor or major fibrosis and not anything in between. Until these tests can measure mid-level damage, the biopsy will remain the gold standard in determining the overall health of the liver.