Hepatitis C: Diagnosis and monitoring

A positive hepatitis C test: what happens now?

If the hepatitis C pathogen (HCV RNA) is detected in the blood, various follow-up tests are carried out in order to inform decisions about treatment and care.

Acute or chronic hepatitis C

Acute hepatitis C is considered to be easily treatable. Up to 90% of people treated during acute infection are able to eliminate the virus.1 If acute hepatitis C is not treated, the infection becomes persistent, or ‘chronic’, in most people (50 to 80%). Hepatitis C is described as chronic if the virus (HCV RNA) is still detectable six months after the first positive RNA test.

Assessing damage to the liver

After diagnosis, it is important to check how much the liver tissue has already been damaged. People with more advanced liver damage or cirrhosis of the liver should be urgently considered for hepatitis C treatment to prevent further liver damage.

Various procedures are used to investigate the condition of the liver tissue.

Blood tests: In addition to levels of the liver enzymes AST and ALT, other blood values are determined, e.g. gamma-GT, thrombocytes, serum albumin, platelet count and bilirubin. These values help in estimating the liver’s ability to function but may not provide a precise guide to the stage of liver disease.

Liver biopsy/liver puncture (an invasive technique): A liver biopsy is considered to be a very useful method for establishing the extent of liver inflammation and any possible scarring of liver tissue (degree of fibrosis).2 In a biopsy, tissue is removed directly from the liver under a local anaesthetic and examined using a microscope. There’s more information on this in the Liver biopsy section.

Elastography (a non-invasive technique): Elastography is a relatively new procedure, which can be used to assess the degree of scarring in the liver, also known as liver stiffness. Doctors can assess how much the liver is scarred by measuring the speed at which sound waves pass through the liver.

Elastography can replace a biopsy in certain cases – in particular, in combination with blood value results.1,3 Elastography devices are not available everywhere, however. For certain investigations a tissue sample is still necessary.

Measuring viral load

The quantity of virus present in the blood is described as the viral load (HCV RNA), which is generally measured in international units (IU) per ml of blood plasma. The higher the viral load, the more virus is detectable in the blood.

In the case of hepatitis C, the viral load has no significance for the progression of liver damage. People with a high viral load do not necessarily experience faster progression of liver damage, nor are people with low viral load protected from liver damage.1The measurement of viral load is nonetheless important because the viral load before treatment is used as a baseline measurement to check how well treatment is reducing virus levels. This helps to predict how likely treatment is to eventually clear the virus from the body. In some situations with certain medicines, the viral load may also influence the recommended treatment duration.   

Testing for viral genotype

There are various different genotypes of HCV. Currently, six different genotypes of HCV are known. The genotypes each carry different genetic information. Around the world, HCV genotypes occur with different frequencies depending on the region. In Europe, types 1, 2 and 3 are the most widespread, with type 1 the most common genotype. On the other hand, genotype 4 is less widespread and genotypes 5 and 6 are very rare in Europe. Treatment recommendations are different for each genotype so it is essential to test the genotype before choosing treatment for hepatitis C.

This information was originally adapted from Hepatitis C: Understanding a silent killer, published by the European Liver Patients Association. It was updated in 2016.

References

  1. EASL Clinical Practice Guidelines: Management of hepatitis C virus infection. J Hepatol 55:245-264, 2011
  2. Ishak K et al. Histological grading and staging of chronic hepatitis. J Hepatol 22:696-699, 1995
  3. Friedrich-Rust et al. Performance of transisient elastography for the stagingof liver fibrosis: a meta-analysis. Gastroenterology 134:960-974, 2008