Definitions
An explanation of key terms used on this site.
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Acute hepatitis C
There is no generally accepted definition of acute hepatitis C infection, but for purposes of investigation and treatment of acute hepatitis C, the following criteria have been used; a clear point of exposure and a positive HCV RNA within six months or a significant rise in serum alanine aminotransferase or seroconversion in which antibody and/or HCV RNA is absent from a first and present in a second sample.
Chronic hepatitis C
Ongoing infection with hepatitis C virus beyond the acute phase.
Mild disease is present when inflammation of the liver tissue is absent or largely confined to the portal tracts with no evidence of fibrous tissue extending between the portal tracts.
Moderate liver disease is described when there is significant inflammation and/or liver cell damage associated with increased fibrous tissue extending beyond the portal tracts but not resulting in nodule formation.
Severe disease occurs when patients have developed bridging fibrosis or cirrhosis (histologically proven or otherwise) of the liver, whether there are clinical signs of liver dysfunction or not.
Genotypes
Many different strains of HCV have been recognised by virological testing. These have been grouped into six categories known as genotypes 1 to 6. There are significant geographical variations in the prevalence of the different genotypes in different parts of the world. In the UK genotype 1 is the most common, followed by genotype 3 and then genotype 2. There are small numbers of patients in the UK infected with hepatitis C virus of genotypes 4, 5 and 6, most of whom acquired the infection overseas.
Sustained viral response
Sustained viral response (SVR) is defined as undetectable HCV RNA in the patient’s serum using sensitive nucleic acid detection techniques, six months after the end of a period of antiviral therapy.
Early viral response
Early viral response (EVR) is either a negative HCV RNA or a two log drop in quantitative HCV RNA levels after starting antiviral treatment. It is measured at 12 weeks for patients with genotype 1.8-10
Rapid viral response
Rapid viral response (RVR) is a negative qualitative HCV RNA measured four weeks after antiviral treatment for patients with genotype 2 or 3.
Non-responder
A non-responder is a patient who after antiviral treatment for HCV has detectable HCV RNA at the end of treatment.
Relapser
A relapser is a patient who after antiviral treatment for HCV has no detectable HCV RNA at the end of treatment, but who does have detectable HCV RNA six months after the end of a period of antiviral therapy.
Current and former injecting drug users
Definitions of current and former injecting drug users vary between different therapeutic environments. Any definition must be considered in the continuum of a chronic, relapsing disease. Precise definition of former injecting drug users is for the most part arbitrary, and in the context of hepatitis C the issue is the potential risk of re-infection with HCV after successful treatment. For the purpose of this guideline an individual infected with HCV may be considered as not at risk of reinfection if they have been non-injecting for six months.
Exposure prone procedures
Exposure prone procedures (EPP) are those where there is a risk that injury to a healthcare worker may result in the exposure of a patient’s open tissues to the blood of the worker. These procedures include those where the worker’s gloved hands may be in contact with sharp instruments, needle tips and sharp tissues (spicules of bone or teeth) inside a patient’s open body cavity, wound or confined anatomical space where the hand or fingertips may not be completely visible at all times.
