Acute Infection – Any infection characterised by signs and symptoms that last for a short period of time. Acute infection with hepatitis C is often very mild, lasts less than 6 months (often less than 12 weeks) and goes unnoticed by many people.
Alanine aminotransferase (ALT) – An enzyme which, when found in the blood in elevated quantities, generally indicates liver inflammation.

Albumin – A circulating protein produced by the liver. In severe liver disease, albumin levels may be low.
Alcoholic liver disease – the term applied to a group of liver problems caused by alcohol. These include fatty liver, alcoholic hepatitis and alcoholic cirrhosis.
Alcoholic hepatitis – inflammation, fatty changes and injury to liver cells caused by alcohol. In this condition, there is usually fibrosis (scarring) present as well.
Alpha fetoprotein (AFP) – a protein produced by certain malignant tumours eg. Hepatoocellular Carcinoma. It’s estimation is sometimes used as a marker for the diagnosis of these tumours or their recurrence. It can also increase in benign liver conditions.
Antibodies – Proteins produced by the immune system in response to bacteria, viruses or other antigenic substances. In the case of hepatitis C, antibodies are produced in response to the virus and indicate past or present infection.
Antiviral – acting against a virus.
Aspartate transaminase (AST) – An enzyme which if elevated in the blood indicates usually, Liver, Muscle or Heart inflammation or damage.
Antiviral treatment – drugs used to suppress and/or eradicate a virus.
Auto-immune hepatitis – A hepatitis caused by the body’s immune system mistakenly recognizing some of its own proteins as being foreign and developing antibodies against them.
Bilirubin – a yellow pigment formed by the breaking down of old red blood cells.
Biopsy – a small sample of tissue, taken for microscopic examination to determine the nature or severity of a disease process.
Blood borne virus – A virus that is transmitted by blood or body fluids that contain blood. Examples are hepatitis B, C and HIV.
CD4 cells (also known as T helper cells) – A type of blood cell that protects the body against viral, fungal or protozoal infection. HIV replicates or multiplies within CD4 cells and destroys them in the process.
Chronic infection – In hepatitis this refers to an infection that is ongoing for more than six months. It does not refer to the severity of the disease.
Cirrhosis – Extensive and, usually, permanent scarring of the liver. Cirrhosis interferes with the normal functioning of the liver.
Co-infection – A general term referring to infection with two or more infectious agents. Hepatitis C co-infection refers to infection with hepatitis C and another blood-borne virus such as HIV and/or hepatitis B.
Combination therapy – The use of two or more types of treatment in combination to achieve optimum results or to reduce toxicity. In hepatitis C treatment, this term refers to a combination of the drugs, Interferon and Ribavirin.
Complementary therapies – The various systems of healing that are not regarded as part of orthodox treatment by the medical profession. These therapies have not been validated using scientific principles.
Disclosure (hepatitis C related) – The act of telling other people that you have hepatitis C. Apart from informing the Blood Bank, individuals are not legally obliged to disclose their hepatitis C status. Disclosure to partners, family, friends, employers, insurers and health workers is a personal and potentially difficult decision.
Endoscopy – Direct visual examination of any part of the interior of the body by means of an optical viewing instrument (endoscope). This procedure is used to examine the stomach (gastroscopy) and colon (colonoscopy).
Extra-hepatic – Outside the liver.
Fatty liver – Fatty liver is the accumulation of fat in liver cells. Another term used to identify this condition is fatty infiltration of the liver or steatosis.
Fibrosis – Scarring. Usually occurs after prolonged inflammation.
Gallstones – The small fig-shaped bag, lying on the under side of the liver, into which bile, secreted by the liver, passes to be stored and concentrated.
Genotype – A term used to describe the specific genetic structure of hepatitis C. The ten identified genotypes are believed to be closely related in their genetic make-up, but differ sufficiently such that each genotype results in a different immune response and response to treatment.
Gilbert’s syndrome – A common, often inherited disease, where the processing by the liver of the pigment bilirubin, is sluggish. This can lead to an abnormal increase in bilirubin the blood and a yellowish tinge to the skin (jaundice).
HAV – The hepatitis A virus.
HBV – The hepatitis B virus.
HCV – The hepatitis C virus.
HCV antibody test – The routine test to determine past or present infection with the HCV virus.
HCV RNA (PCR) – directly detects viral sequences (HCV RNA) in serum. If positive, indicates present infection. This test can be qualitative in which case the result will be either positive or negative, or quantitative in which case the amount of virus is measured and usually reported in International Units (IU).
Haemochromatosis – A genetic disorder of iron regulation (metabolism) in the body. This results in excess iron being stored in the tissues. Iron accumulates over a long period of time, causing “iron overload”.
Haemophilia – A group of inherited bleeding disorders in which there is a deficiency in factor 8 or 9, necessary for coagulation of the blood. Haemophilia almost exclusively affects males.
Hepatitis – A general term, meaning inflammation of the liver.
Hepatocyte – A liver cell. 
Hepatoma – Primary liver cancer, more correctly termed hepatocellular carcinoma.
Hepatotoxic – Any substance that causes harm to the liver.
HIV – The Human Immunodeficiency virus.
Household transmission – The term given to the transmission of a virus in a household setting. In the case of hepatitis C, household transmission is extremely rare.
Immune system – The body’s defence against any foreign substance. A major function of the immune system is to combat infections caused by micro-organisms, and it also acts to protect against the effects of drugs, toxins and cancer cells.
Interferon – A substance produced naturally by the body to help defend itself against viral infection. The administration of synthetically manufactured interferon alpha in large doses can help to reduce the amount of hepatitis C in the blood and slow down or stop the disease process.
Monotherapy – The use of one type of treatment. In the case of hepatitis C, this refers to the use of Interferon on its own. Monotherapy is now only used in patients who cannot tolerate Combination therapy.
Liver function tests – This refers to the measurement of a number of enzymes in the blood which, if elevated, infer liver inflammation. Despite the name, liver function tests do not measure true function of the live
NASH – Non alcoholic steatohepatitis – fat in the liver in association with inflammation with or without scarring.
Needlestick injury – Refers to an injury with a needle or other sharp implement.
Non-A, non-B hepatitis – Before hepatitis C was identified in 1989, this term was used to describe any hepatitis virus that was not caused by either hepatitis A or hepatitis B. It is now thought that the majority of cases of non-A, non-B hepatitis were hepatitis C.
Oesophageal varices – Varicose veins occurring at the lower end of the oesophagus (gullet). Can occur in conditions such as cirrhosis of the liver.
Pegylated interferon – slow release interferon, administered once a week. Pegylated interferon is emerging as the most effective treatment for hepatitis C, when used in combination with Ribavirin.
Platelets – Components of blood formed in red bone marrow, which congregate at eh site of an injury to form a clot. They are essential for coagulation or clotting.
Polymerase chain reaction (PCR) – A laboratory technique that amplifies the genetic material of a virus to a level that can be detected. The presence or absence of the virus can then be determined. PCR is used to directly measure for the hepatitis C infection.
Primary biliary Cirrhosis – A slowly progressive disease of the bile ducts inside the liver. Inflammation of the bile ducts can eventually lead to scarring and this can sometimes cause blockage and a back flow of bile.
Primary sclerosing cholangitis – In this condition, the walls of the bile ducts become inflamed (cholangitis) and the inflammation causes scarring and hardening (sclerosis). This results in narrowing of the bile ducts. 
Prognosis – A prediction of the probable outcome of a disease, based on the condition of the person and the usual course of the disease as observed in similar situations.
Prothrombin time – An indirect measure of the proteins produced by the liver which will help with blood clotting. This is an example of a true liver function test.
Quality of life – A  measurement, usually subjective, of the complete state of physical, mental, emotional and social wellbeing, and not merely the absence of disease.
Ribavirin – A drug that alters the body’s immune response to viruses. Used in combination with Interferon in the treatment of hepatitis C. Ineffective when used alone. See Combination Therapy.
Subcutaneous injection – The introduction of a hypodermic needle, inserted at a 45% angle into the tissue beneath the skin. Interferon is administered in this way into the fat of the abdomen or the outer thigh.
Sustained virological response (SVR) – In reference to hepatitis C, this refers to the elimination of the virus following treatment. This results to an improvement in symptoms, and the reduction of potential long-term complications of the virus such as cirrhosis. If the HCV RNA is undetectable 6 months after the cessation of treatment, the patient is said to have achieved a sustained viral response. Neally all patients who do not have detectable virus 3 months after therapy achieve a sustained viral response.
Triple therapy - Use of interferon, ribavirin and a protease inhibitor (telaprevir or boceprevir)
Ultrasound examination – High frequency sound waves are transmitted through the skin and reflected by the internal organ, the pelvis, the heart and the major blood vessels. These “echoes” form a picture on a screen which can be examined for abnormalities.
Vaccine – A substance that stimulates and immune response and renders a person immune to a particular infection. There is no vaccine for hepatitis C, but vaccines are available for both hepatitis A and hepatitis B.
Viral load – The amount of virus circulating in the blood. In the case of hepatitis C, the viral load is usually measured by a PCR quantitative test. The result is given in the number of viral particles per ml of blood or international units per ml.