Types of tests - Monitoring tests
After confirming that a person has hepatitis C (see Types of tests – Diagnostic tests for more information) a healthcare provider will likely recommend a variety of other tests to monitor liver health and look for other health conditions that might impact the course of hepatitis C. After that, the frequency with which a person is tested (for example just once, every 6 months or yearly) and the length of time he or she is monitored depends on the individual and his or her healthcare provider.
These other tests cannot tell if a person has hepatitis C. The objective of these tests is to try to monitor the degree of damage, determine whether the liver is functioning differently and see how quickly the damage is happening. This is important information that helps a person and their healthcare provider decide if and when to start treatment, informs how well lifestyle changes or medical interventions are working and reveals if a person is experiencing or is at risk for experiencing severe outcomes such as cirrhosis, liver failure or liver cancer.
Most monitoring tests are covered by provincial health insurance. When a test is not covered, some doctors will bill clients for the cost and some doctors will not. Clients can ask healthcare providers to identify in advance any tests they will be charged for.
A liver biopsy measures the degree of scarring (also called “fibrosis”) and the amount of inflammation (also called “activity”). It is considered the gold standard for measuring the extent of liver damage.
The procedure - During a liver biopsy, a small piece of the liver is removed with a needle. Before doing this, the healthcare provider numbs the skin and area under the skin around the needle’s entry point. The needle is only inserted into the body for a very short-time (less than a second).
Biopsies are done as an outpatient procedure, meaning the person gets to go home the same day. In the case of liver biopsies, the person is usually sent home 2 to 6 hours after the procedure.
Risks - About half of the people who have a liver biopsy do not have any pain at all. The other half experience some pain around the needle’s entry point and in the right shoulder. Severe complications are very rare but they exist. Less than 1% of people who have a liver biopsy experience internal bleeding as a result. A healthcare provider will weigh the benefits and risks of this test before deciding the best course of action for a patient.
How to interpret results - There are three scales used to evaluate liver biopsies:
- the Knodell Histological Activity Index (HAI)
- the Ishak or Modified HAI
It is important to know which scale is used because a particular value in one system does not mean the same thing in another. Across Canada, METAVIR is most commonly used to evaluate liver biopsies for people with hepatitis C.
For each scale, a variety of liver characteristics are looked at and represented by a number value. These individual number values are added together to create a complete picture of scarring and inflammation, expressed as a final single value. If a person has multiple biopsies, the healthcare provider will look at how the value of each individual characteristic changes or stays the same among tests, and not just the final value. It is possible that the final value stays the same but some individual characteristics may have improved and some may have gotten worse.
The chart below compares the value ranges of these scales and some meaningful results.
|METAVIR||Knodell HAI||Ishak or Modified HAI|
|How many liver characteristics are examined?||2||4||5|
What is the range of final values?
|0-22 where 0 is no damage and 22 is severe|
0-24 where 0 is no damage and 24 is severe
What value indicates moderate fibrosis?
Fibrosis score of 2
Fibrosis score of 3
What value indicates cirrhosis?
Fibrosis score of 4
Fibrosis score of 5 or 6
Recently, less invasive tests for liver damage are becoming more popular. Recently, less invasive tests for liver damage are becoming more popular (see Ultrasound, Transient Elastography and Liver Enzyme sections, below). The types of liver tests a person has depends on many factors such as the person’s general health, his or her preference, the availability of less invasive tests and the doctor’s preference. It can also depend on provincial regulations. For example, some provinces pick one specific type of test as the standard to be given when a doctor is considering a person for treatment. (Information on mandatory testing before treatment coverage can be found in Treatment Coverage in Your Region).
The main reasons a healthcare provider might recommend an ultrasound for someone who currently has hepatitis C or has had it in the past is to get an overall view of the liver’s shape and size, rule out any obvious causes of abnormal liver tests and determine if there is any evidence of a cause other than hepatitis C, and see if there is any sign of advanced fibrosis or cirrhosis. It is also used to screen for hepatocellular (liver) cancer. The College of Family Physicians of Canada recommends that people with cirrhosis screen for hepatocellular cancer every 6 months.
The procedure - An ultrasound is fairly portable and can be performed in locations other than a hospital. The person lies on his or her back with the right arm raised behind the head and a probe is placed on top of the skin over the ribcage.
The probe sends out a sound wave that travels through the liver and echoes back to the probe. A computer measures the speed and strength of the echo to create a picture of tissues and organs inside the body. The whole process takes a few minutes.
Risks - There are no risks associated with the ultrasound.
How to interpret results - If the healthcare provider thinks he or she sees a tumor in the picture created by the ultrasound, he or she will order an X-ray to get a better look.
An ultrasound does not measure fibrosis directly. The healthcare provider will use the ultrasound to measure the elasticity or stiffness of the liver and identify a corresponding level of fibrosis. The stiffer the liver is, the more severe the degree of fibrosis.
Also known by its brand name, Fibroscan, transient elastography is an advanced form of an ultrasound. It allows a healthcare provider to measure fibrosis in the liver in a non-invasive way. Fibroscan machines are available in some liver centres in Canada but are not widely available.
The procedure - The procedure is very similar to an ultrasound. The transient elastography (Fibroscan) machine is fairly portable and can be performed in locations other than a hospital. The person lies on his or her back with the right arm raised behind the head and a probe is placed on top of the skin over the ribcage.
The probe sends out a sound wave that travels through the liver and echoes back to the probe. A computer calculates the speed and strength of the echo to measure the elasticity or stiffness of the liver.
Risks - There are no risks associated with this technology.
How to interpret results - The transient elastography (Fibroscan) measures fibrosis using the elasticity or stiffness of the liver; the stiffer the liver is, the more severe the degree of fibrosis. A transient elastography (Fibroscan) result presents liver stiffness as a number measured in the unit kilopascals (kPa). The healthcare provider then uses a reference chart to identify a degree of fibrosis that corresponds to that number. The healthcare provider might also take into consideration results from other tests when identifying the corresponding fibrosis level on the reference chart.
Transient elastography (Fibroscan) is very effective at identifying the absence of fibrosis or the presence of severe fibrosis and cirrhosis but it is not as accurate as a biopsy when it comes to identifying less severe stages of damage. Because transient elastography (Fibroscan) is faster, less expensive and less painful compared to a biopsy, a healthcare provider may first use transient elastography and follow that with a biopsy if the results are not clear.
The more damage the liver sustains, the less able it is to complete its 500-plus functions. There is a battery of tests that healthcare providers can use to check how well the liver is working, including:
- prothrombin time or INR: Prothrombin is a protein that is responsible for helping blood to clot.
- bilirubin: This substance produces the yellow colour of jaundice and is produced when the liver breaks down old red blood cells.
- albumin: A major blood protein, albumin is produced by the liver and is used in transporting some molecules through the body and maintaining fluid levels in the blood.
The procedure - These tests require a blood sample taken by a healthcare provider, which he or she then sends to a lab for analysis.
Risks - The main risks associated with blood tests are bruising and some pain around the needle’s entry point.
How to interpret results - The healthcare provider will compare the person’s test scores with a normal range. When one or more scores are outside the normal range, this may indicate that the liver is not working as well as it should be and that something is damaging it. However, scores can be affected by many factors other than hepatitis C, including other viruses, diet, alcohol, medicines and other toxins. More testing may be needed to identify what is damaging the liver.
These tests measure levels of liver enzymes (such as ALT and AST) in the blood. Liver damage can lead to higher-than-normal levels of liver enzymes in the blood, so these tests can flag if something is damaging the liver and alert a healthcare provider to do more testing. The inflammation can be caused by any number of factors, including hepatitis viruses, diet, alcohol, medicines and other toxins. Other liver enzyme tests include ALP, LDH and GGT.
People taking treatment for Hep C may have liver enzyme tests to monitor how the treatment is working.
Liver enzyme tests follow the same procedure, risks and interpretation of results as liver function tests, above.
There are other tests a healthcare provider might recommend in order to monitor what is going on in a person’s body. The list could include:
- complete blood count
- creatinine test
- alpha fetoprotein test
- thyroid test
- iron test
- lipid profile or total cholesterol
- pregnancy test
- HIV test
- Hep A antibody test
- Hep B antibody test
- Magnetic resonance imaging (MRI)
Information on any of these tests and others - including why and how they are administered and what the results mean - is available through Lab Tests Online’s Test Index. This index is published by the American Association for Clinical Chemistry.