Testing

There are a number of tests used in diagnosing and monitoring the hepatitis C virus. Whether to be tested for hepatitis C or not is a matter for each individual to decide. People who have been feeling unwell and may have been exposed to the virus through IV drug use, blood transfusion prior to 1990, a needle stick injury, or unsterile tattooing or piercing may wish to consider getting tested.

It is recommended that for children testing should only be carried out at 18 months of age or older. Before this time, due to the passive acquisition of the mother’s antibodies, the chances of getting an incorrect result are high.

No matter what test is performed, people should always ask for a photocopy of their test results and keep these together in a central location. This way if a second opinion is sought or there is a change of treating doctor, all the relevant information is easily accessible.

ANTIBODY TEST

The initial screening test for hepatitis C is a simple blood test. To fight the hepatitis C virus the body produces antibodies. The antibody test does not check for the virus itself but for the antibodies to hepatitis C produced by the body. Antibodies are specific to particular viruses and will remain in the body for many years to guard against further infection from that virus. Due to the nature of the hepatitis C virus, antibodies are only able to eliminate the virus for around 20%-25% of people.

The antibody test therefore indicates whether the person has been infected by the virus via the presence of antibodies. This test does not determine whether or not someone still has hepatitis C since the antibodies will remain in the blood even if the body has cleared the virus. The test also cannot tell how long ago the person was infected and for how long they might have had hepatitis C.

After catching hepatitis C, it may take the body up to 6 months to sero-convert, which means develop antibodies. This is called the window period. During this time, someone with an active infection could still show a negative or indeterminate antibody test, since his or her antibodies are not fully developed.
Antibody test results are usually clearly positive or negative, but sometimes they come back as indeterminate. In this case, a repeat test will be required. A repeat test is also always performed to confirm positive results.

The hepatitis C antibody tests can be claimed on Medicare and are free if performed by a doctor who bulk bills. People who get a positive test result and have no history of risk factors are encouraged to check with their doctor that the laboratory has repeat tested the blood sample.

LIVER FUNCTION TEST

This test is also a blood test and is used to detect abnormal levels of specific enzyme production in the liver. When the liver is attacked by the hepatitis C virus it gets inflamed. One of the responses of the liver to inflammation is to produce enzymes. These enzymes are often very specific to certain viruses or conditions. One of the signs that the hepatitis C virus is causing inflammation of the liver is raised levels of ALT (alanine aminotranferase) in the blood. For people who are hepatitis C positive, ALT is the most commonly monitored enzyme in liver function tests.

A positive result on an antibody test and elevated ALT levels on a liver function test provide a fairly good indication that an individual is still infected with the hepatitis C virus. On the other hand, a positive result for on an antibody test combined with normal ALT levels over a period of 6 months, might mean that the body has cleared the virus and only the hepatitis C antibodies remain. A person with these results may consider having a PCR test (see below).

Doctors and liver specialists often use differences in liver function test results over time (in combination with physical symptoms or other signs of liver disease) to evaluate the progression of hepatitis C in their patients. Liver function tests can be done monthly, quarterly, twice a year or annually, depending on the individual case.

It is important to remember that ALT levels can fluctuate markedly over even short periods of time and can be affected by other factors, such as stress, alcohol consumption, and diet. In addition, while elevated ALT levels are a measure of inflammation to the liver, there is no clear correlation between high ALT levels and liver damage.

Due to differences in technology, ‘normal ranges’ quoted by laboratories may differ. This means ALT result from one laboratory should not be compared with results from another laboratory.

POLYMERASE CHAIN REACTION (PCR) TEST

This is also a blood test. The term PCR refers to the actual laboratory technique that amplifies the virus’ genetic material to a level that can be detected. The technique consists of many stages and is fairly expensive.

In relation to the hepatitis C virus, the technique may be used to test for the following three factors:

• The presence or absence of the virus in the blood
• The level of virus present in the blood (viral load)
• The genotype (type) of the virus

Presence or absence of hepatitis C
The information from a PCR test is useful in interpreting unclear antibody test, as it shows whether someone still has the virus in their body, and therefore has chronic hepatitis C. Like the hepatitis C antibody test, the PCR test cannot tell how long someone has been infected. The PCR test is generally used for assessing someone for treatment and for monitoring his or her response to treatment (see the section on treatment).

The Medicare rebate may apply to the first part of the PCR test, which detects the presence or absence of the hepatitis C virus. At the current time, however, a Medicare rebate is only available for people who fulfil the following criteria:

• People who have had a positive hepatitis C antibody test combined with a normal liver function test results on two occasions six months apart, or
• People who have had inconclusive hepatitis C antibody test results, or
• People who have a weakened immune systems (due to HIV/AIDS) and wish to confirm whether they are hepatitis C positive, or
• People who have experienced a risk exposure (such as a needle stick injury) and wish to confirm during the ‘window period’ whether they have contracted the hepatitis C virus.

Viral Load
The PCR testing technique is also used to detect the amount of the hepatitis C virus in the blood, that is, the viral load. The viral load in an individual and between individuals can fluctuate from undetectable to millions. Usually, the lower the viral count the higher the probability that pharmaceutical treatment will be successful.

Receiving a PCR negative result (that is, no virus is detected in the blood) does not necessarily mean that the virus has disappeared completely; it may still be present at undetectable levels.
The results of a viral load test are expressed in different ways according to the protocols of the testing laboratory. Therefore, it is not recommended to compare the results from different laboratories.

Genotype
There are many genotypes of the hepatitis C virus and the particular genotype of hepatitis C that is causing an infection can also be determined through a PCR test. It is essential for people considering pharmaceutical treatment to know which genotype of the virus they are infected with, as this will determine the length of their treatment as well as the affect the probabilities of success with treatment.

LIVER BIOPSY

This procedure is regarded as the most reliable to assess the health of the liver. It is also a requirement for those considering treatment. A biopsy is a minor surgical procedure in which a specialist takes a tiny piece of the liver for laboratory examination.

While a liver biopsy is generally considered a safe operation, there is always the risk of bleeding or other more serious complications. Accordingly, the decision to have a liver biopsy should not be taken lightly. The procedure is not recommended for people with haemophilia or other blood clotting conditions.
Nowadays it is generally standard procedure that an ultrasound or CT scan is used to pinpoint an appropriate site for the biopsy. This minimises the risk of complications such as causing too much bleeding or hitting something other than the liver. People undergoing a liver biopsy may wish to check that an ultrasound or scan has been performed.

Liver biopsies usually involve the following:

• The skin is sterilised and a local anaesthetic is administered.
• A very small needle is passed between the ribs and into the liver.
• A thin matchstick size sample of the liver is removed.
• The patient is required to lie still for approximately four hours after the procedure to make sure that there is no bleeding.

While for many people the operation is pain free, others experience some discomfort. Some people, for example, have reported a pain in the right shoulder that makes it difficult to lie still after the procedure. Some people also experience pain at the site of the biopsy and others have reported a temporary feeling of unwellness during and after the biopsy. For many people, painkillers may be necessary after the procedure in order to decrease discomfort.

A liver biopsy tests for both the extent of the inflammation (often differentiated according to parts of the liver, as either lobular or portal inflammation) and the damage to the liver (described as the amount of fibrosis). The amount of fibrosis can also be referred to as the stage of the liver and the extent of inflammation as the grade.

For more information about this topic go to the Australian Hepatitis Council web site at www.hepatitisaustralia.com or see Frequently Asked Questions on the NSW Hepatitis C Council website at www.hepatitisc.org.au.

Please note: This information DOES NOT aim to replace the advice that would be provided by a doctor or other health care worker. People who have hepatitis C should regularly see their doctor, who can provide monitoring, up-to-date information, advice, and counselling if needed.