Getting tested for hepatitis C can be difficult and NEP research suggests PWID are getting tested but don't understand what those test results mean. Testing can be done in most health arenas such as your GP, private and public testing clinics, sexual health centres and in some instances at Needle Exchange outlets.
When you get tested for HCV the first thing that is often done is your blood will be tested for HCV antibodies. When your body detects a virus, it develops antibodies to try and fight the virus. So the antibody test shows if you have been EXPOSED to the virus, not that you currently HAVE IT. This antibody test is called the ELISA (HCV) test.
Hepatitis C antibodies will still be detected even if you have cleared the virus so to be sure it is often necessary to do a PCR test which will find out if your exposure to the Hep C virus has become an infection with the virus.
If the PCR test says you are infected with the Hep C virus, then you would have more tests to find out how your liver is doing. This group of tests are collectively known as LFT's or Liver Function Tests and they measure key enzymes in your liver and blood that provide markers to the inflammation the liver may be experiencing due to the circulating virus.
There are two problems with just having an antibody test on its own.
1. The antibody test can remain negative up to six months after infection (the window period) and should therefore be repeated at least six months after the last possible exposure. During this window period an acutely infected person may be highly infectious. In this situation only testing for the virus itself (PCR test) will detect the infection.
2. A possible antibody result dopes not discriminate between previous and active infection. A positive antibody result simply confirms exposure to the hepatitis C virus. Therefore people who have managed to eradicate hepatitis C infection either naturally or though treatment will still show a positive antibody test result.
Why do Genotypes matter?
It is important to find out what genotype of hepatitis C a person is infected with, as this helps them predict how the person will respond to antiviral treatment: genotype 1 is generally associated with a poor response to interferon alone, whereas genotypes 2 and 3 are more associated with more favourable responses.
The current best treatment for hepatitis c is pegylated interferon in combination with ribavirin. This treatment significantly improves treatment responses for all genotypes.
There are six main types of hepatitis C (Genotypes 1-6) and 21 subtypes. All hepatitis C genotypes have the same risk of developing cirrhosis. However, Genoptype 1 is much less responsive to antiviral therapy than types 2 and 3 and the treatment course is generally longer.
Genotypes 1,2 and 3 have a world wide distribution. Types 1 a and 1b are the most common, accounting for about 60% of global infections.
NZ has a mix mainly of genotypes 1,2 and 3; the most common in NZ are type 1a, 1b and 3.
Rapid Screening Tests
Quick testing technology has very limited application in New Zealand. The Needle Exchange Programme has used dried blood spot specimen taking when conducting its seroprevalence studies among needle exchange attendees since 1997.
Quick testing kits can test for blood, plasma, oral fluid and dried blood spot and has now reached a stage in its evolution to warrant it being used in the community setting to engage clients affected by hepatitis C into treatment options and further understanding the state of the virus condition in and individual.