Tests before, during and after treatment are primarily designed to see whether you need treatment, to see whether the treatment is working and to monitor any side effects the treatment may be having on you.
This section looks at the key tests in relation to treatment and how they are interpreted.
In August 2006 NICE treatment guidelines were updated to include people with mild to moderate disease. This means it is no longer necessary for consultants to order a liver biopsy to check if the disease is in the moderate to severe category. However, a biopsy may be needed for other reasons.
A biopsy shows inflammation and scarring. Inflammation is an indication of the ongoing assault on the liver and is most commonly measured on the Ishak scale of 0 to 18 (where 0 is none and 18 is the maximum). Scarring is the result of past damage to the liver and is usually measured either on the Ishak scale of 0 to 6 (where 0 represents no scarring and 6 cirrhosis) or the Metavir scale of 0 to 4 (where 0 represents no scarring and 4 cirrhosis). In between no scarring and cirrhosis the numbers measure the degree of fibrosis. The higher the number, the greater the degree fibrosis will be.
A pre-treatment biopsy may be useful for comparing with a biopsy taken some time after treatment has finished because, in some cases, interferon can cause a reversal in both inflammation and scarring.
A genotype test is the basis for deciding the length of treatment. (again, where is RVR in this?
- Types 2 and 3 are recommended to do treatment for 24 weeks
- Types 1,4, 5 and 6 are recommended to do treatment for 48 weeks
Liver Function Test
A liver function test measures a whole range of functions of the liver, all of which can indicate, to some degree, the health of the liver. During treatment particular attention is paid to the AST (aspartate aminotransferase) and ALT (alanine aminotransferase) levels. These are generally above normal in people with hepatitis C and are expected to return into the normal range (0-40) if treatment works. An early fall towards normal levels within the first 3 months is a good sign, but normalisation may not occur until after treatment has finished.
Full Blood Count
3 indicators are closely monitored, as very low levels are dangerous. If they get too low, the dose may have to be cut or treatment stopped altogether:
- Haemoglobin, which is required to transport oxygen around the body. A drop in haemoglobin indicates anaemia and because ribavirin can cause levels to fall a dose reduction may be required.
- Platelets, which are required for blood clotting. A drop in platelets can indicate thrombocytopenia which can be caused by interferon.
- Neutrophils, which are part of white blood cells and fight infection. A drop in neutrophils is called neutropenia and means that people can be at greater risk of picking up infections. Interferon can lower levels of neutrophils.
A thyroid function test is used to check for thyroid disease. This can be either an overactive (hyperthyroidism) or an underactive (hypothyroidism) thyroid. Your thyroid gland secretes hormones that regulate growth and development by controlling your metabolism. Hyperthyroidism increases your metabolism, whereas hypothyroidism decreases it. These are measured by the relative levels of thyroid stimulating hormone and thyroxin.
The test will also measure whether you have any thyroid antibodies, which could indicate a tendency to develop thyroid disease, which can occasionally be caused by interferon.
Because of the dangers of ribavirin to foetuses in the womb, pregnancy tests are required before treatment starts (if you are pregnant, you cannot start treatment) and regularly throughout.
This is the test that shows whether the virus can be detected in your blood.
A quantitative PCR test will measure the amount of virus in your blood. This is measured before treatment starts to determine a reference or baseline level. A follow-up test will be performed after 6 months, although sometimes after 3 months. If treatment is working, you should expect to see at least a hundred-fold drop (often referred to as a 2 log drop) in your viral load. So, if you started treatment with a viral load of 2 million parts per mil, you should expect to see it drop to 20,000 or lower, certainly less than 100,000.