PCR Review from Australia
petsnpeople
(From the Hep C Review, Ed29 June 2000)
PCR testing
The HCV antibody blood test detects antibodies that our immune system makes
when HCV enters the body. Antibodies are still present even after the
infection has gone. Unlike the antibody test, the PCR test detects the actual
hepatitis C virus so confirms that the infection is still present. PCR stands
for polymerase chain reaction. It is a type of Nucleic Acid Amplification
Test (NAAT). These tests detect tiny amounts of virus by duplicating the
virus in the laboratory until there is enough of it to measure. Viruses
contain nucleic acids as the main part of their structure. This new cutting
edge technology is pretty extraordinary considering it involves finding and
measuring a virus so small that 30 billion would fit on a full stop! (School
of Mathematics, University of Sydney).
There are three types of PCR tests: HCV PCR viral detection test (looks for
the virus, sometimes called 'qualitative test') HCV PCR viral load test
(looks for the virus and estimates how many HCV viruses per ml of blood,
sometimes called 'quantitative test') HCV PCR genotype test (looks for the
virus, and determines which particular subtype/s of HCV a person has).
PCR viral detection test
PCR viral detection tests are mainly used as a confirmatory test when an HCV
antibody test result is inconclusive. They are also used to check within the
6 month window period following a risk incident - when antibody tests are
still unreliable - if a person has contracted HCV. They can also be used to
determine if someone is viral positive in the event of consistently normal
liver function tests and lack of symptoms.
PCR viral load testing
PCR viral load tests estimate the amount of hepatitis C virus circulating in
someone's blood. It is believed that during interferon treatment, these tests
will better monitor whether the therapy is working - as opposed to monitoring
liver function. It's also believed that initial PCR viral load testing as
early as 2-4 weeks into treatment will identify people who wouldn't respond
over the full 12 months.
PCR genotype testing
PCR genotype testing can determine what subtype of hepatitis C virus a person
has. This is useful information as it's been shown that of the known major
sub-types, interferon treatment seems to work better in people with genotype
subtypes 2 or 3. People who are really keen for interferon may not worry too
much about PCR genotyping but for those who are unsure whether to try the
treatment or not, the PCR genotype test could help guide their decision.
Availability (diagnostic)
PCR testing has been covered under the Medicare Benefits Schedule since July
1998 (Item No. 69444) for use in certain circumstances: 1 Medicare covers
only the basic PCR HCV viral detection test - as opposed to viral load or
genotype tests. 2 Medicare will cover only one PCR test - each year - for
any one person. 3 Medicare covered PCR tests are available only in limited
situations - including: a) people who have had a positive HCV antibody test
and who have normal liver function test results on two occasions six months
apart; or b) people who have inconclusive HCV antibody test results; or c)
people who have weakened immune systems (eg. HIV/AIDS) and want to confirm
whether they are hepatitis C positive or not; or d) detecting acute
hepatitis C, prior to seroconversion, in those people who have signs of acute
hepatitis yet other causes have been excluded (eg. hep A or hep B). PCR
testing is made available in these cases where this information is considered
necessary for the clinical management of the person's hepatitis.
Availability (treatment monitoring)
As mentioned above, PCR genotype and PCR viral load tests have emerged as the
most useful tools for predicting and monitoring response to interferon
monotherapy or Rebetron combination therapy. All three variations of PCR
testing will soon be covered under the Medicare Benefits Schedule (under
certain circumstances) but the date of effect has not yet been confirmed. It
is believed that coverage will take effect some time this year. The request
for the above monitoring tests are limited to treating specialists and are
for patients with confirmed hepatitis C (antibody or previous PCR) who
undertake antiviral therapy depending on the result of testing. These
additional funded access arrangements allow for: 1 x PCR genotype test - when
initially considering treatment options. 1 x PCR viral load test prior to
therapy - should someone decide to proceed with interferon or combination
therapy. 4 x PCR viral detection tests prior to and over a 12 month
treatment/follow up period - to help monitor treatment response. The maximum
number of PCR viral detection tests for any course of treatment is four,
including any provided under Item 69444 (above).
Test limitations
Despite improvements in the sensitivity of PCR technology, it's important to
assess HCV viral status on the basis of a series of PCR tests over an
extended period, rather than on the basis of a single PCR test result. This
is because it is possible for levels of hepatitis C virus in the blood stream
to fluctuate so low that the PCR test won't pick it up. Thus, someone who
tests PCR negative may still have a current infection. People who are
currently on, or have recently undergone, interferon treatment need to be
especially cautious because of the greater fluctuations in viral levels due
to treatment. ------------------------------------------------ Paul Harvey
Hepatitis C Council of New South Wales Australia
--
Kathy M.
I donate Free-ly (http://community.webtv.net/petsnpeople/DonateFREEly
Sent via Deja.com http://www.deja.com/
Before you buy.
Firebird
(petsnpeople) wrote:
> Good general PCR info and some things specific to Australia
<snipped>
> to treatment. ------------------------------------------------ Paul
> Harvey
> Hepatitis C Council of New South Wales Australia
>
> www.hepatitisc.org.au
So one wonders what will be the result of an e-mail to the above address
asking them if you have their permission to post their work in two
newsgroups? Surely these articles have copyrights?
Alan
Firebird
Swagman) wrote:
> The only thing that is copyright in Australia is my Niagara-falls
> Stop nit picking Pom
Get fucked, Aussie!
Alan
Spinach - OT Weed
<sn...@crackle.pop.net> Turning his attention with an intense look
while throwing lovely flowers from his pretty basket to those in the
audience gathered around went on to say:
>Fire...@plutonic.idps.co.uk
>The Pom
>
>>So one wonders what will be the result of an e-mail to the above address
>
>This would be the reaction if you sent such a email
>" Have a look at what some silly prick emailed us "
>" What a wanker, ha-ha-ha "
>
>>asking them if you have their permission to post their work in two
>>newsgroups? Surely these articles have copyrights?
>
>The only thing that is copyright in Australia is my Niagara-falls
>Stop nit picking Pom
>
>
>Hepatitis C Council of NSW Australia = Good Mate to a lot of suffering
>people
>
I think he likes you, Al. Better keep your curtains drawn against
Peeping Toms.
>
>
>
>
>
Spinach
Firebird
> I think he likes you, Al. Better keep your curtains drawn against
> Peeping Toms.
I'm really wondering how come he knows Cockney rhyming slang and I
don't.
Alan
Spinach - OT Weed
fire...@cabatit.junglelink.co.uk (Firebird) Turning his attention
with a fierce gleam in his eye mention these following:
Star struck?
Doug
--
Doug
Spinach - OT Weed <n_z...@yahoo.net> wrote in message
news:3939df2f...@news.jps.net...
> On Fri, 26 May 2000 18:32:06 +1000, Jolly Swagman
> <sn...@crackle.pop.net> Turning his attention with an intense look
> while throwing lovely flowers from his pretty basket to those in the
> audience gathered around went on to say:
>
> >Fire...@plutonic.idps.co.uk
> >The Pom
> >
> >>So one wonders what will be the result of an e-mail to the above address
> >
> >This would be the reaction if you sent such a email
> >" Have a look at what some silly prick emailed us "
> >" What a wanker, ha-ha-ha "
> >
> >>asking them if you have their permission to post their work in two
> >>newsgroups? Surely these articles have copyrights?
> >
> >The only thing that is copyright in Australia is my Niagara-falls
> >Stop nit picking Pom
> >
> >
> >Hepatitis C Council of NSW Australia = Good Mate to a lot of suffering
> >people
> >
> I think he likes you, Al. Better keep your curtains drawn against
> Peeping Toms.
>
> >
> >
> >
> >
> >
> Spinach