The ME Association is receiving questions from people with ME/CFS and from health professionals about various aspects of XMRV blood testing here in the UK. We have therefore summarised all the relevant information that is available at present.
General Advice on XMRV blood testing:
Our general advice regarding XMRV blood testing remains as follows:
Until it has been firmly established that there is a definite link between XMRV and ME/CFS, and an accurate method of testing for the virus in blood samples has been agreed by international retrovirologists (virologists who specialise in this type of infection), there is no point in people with ME/CFS spending a large sum of money on private laboratory testing for XMRV.
This is because:
1 With only one research study so far supporting a link to ME/CFS, and three validation studies not finding any evidence of XMRV in people from Europe with ME/CFS, the link between XMRV and ME/CFS remains uncertain.
2 There is no evidence at present to show that XMRV is a disease causing virus in relation to ME/CFS, or that it causes ME/CFS.
3 Being XMRV +ve does not confirm that someone has ME/CFS – the presence of XMRV cannot therefore, in our present state of knowledge, be used as a diagnostic marker for ME/CFS.
4 Being XMRV+ve is not, at present, an indication for treatment with antiviral medication, or any other speculative prescription-only medication. Antiviral drugs such as AZT can have serious side-effects (including development of myopathy and neuropathy – muscle and nerve damage) and given the fact that the NICE guideline on ME/CFS states that antiviral medication should not be prescribed in ME/CFS, doctors in the UK are unlikely to be willing to prescribe antiviral medication in the current state of uncertainty.
5 The current methods for testing for XMRV may be producing either false positive results or false negative results. The accuracy of commercial testing has not been properly validated.
6 Individual counselling and medical advice should be available to people who take an XMRV test – in exactly the same way that it is given to people before and after taking an HIV test. In the case of commercial XMRV testing, this sort of advice does not appear to be available in the private sector. From the ethical point of view, the availability of informed medical input also apply to research studies if the XMRV result is going to be given to the people involved.
There are further XMRV research studies in progress in Australia, Europe and the USA, and the results will be gradually appearing over the coming months. Hopefully, a clearer picture will have emerged by the end of the year as to whether XMRV is linked to ME/CFS. If this is the case then further research will then need to examine whether the virus is actually involved in causing symptoms in ME/CFS (it may just be a harmless passenger) and whether appropriate antiviral medication needs to be assessed in clinical trials.
XMRV testing: NHS and Private
Testing for XMRV is not available on the NHS and we are not aware of any private UK pathology labs who are testing for this virus, or have the expertise to do so. So the only way to get an XMRV test is to send a blood sample to an overseas laboratory. Further information on the availability of overseas XMRV testing can be found here: http://www.xmrvtesting.co.uk/
One of the commercial laboratories in the US that has been offering XMRV blood tests has now withdrawn this facility until the scientific controversy surrounding XMRV and ME/CFS has been resolved >>http://www.codiagnostics.com/XMRV/diseases.php
Extract from the codiagnostics statement on XMRV:
While XMRV is an infectious retrovirus and will certainly impact the medical community, people with CFS may be better served by waiting for further studies connecting XMRV to CFS prior to investing in a diagnostic. Those who choose to be tested anyway should understand that any testing at this point is research only in aiding to establish the actual prevalence of the virus in the CFS community. Until the scientific controversy surrounding XMRV is resolved, Cooperative Diagnostics has removed its test from the market and will participate in research only.
What should people in the UK do if a blood test shows that they are XMRV +ve?
If you have been informed that as a result of a blood test you are XMRV +ve, this result should be discussed with your GP and/or ME/CFS specialist. The ME Association cannot provide individual advice on lifestyle or drug management in this situation. This has to be a decision for you and your medical adviser.
Retesting XMRV status in the UK
The MEA believes that a small but important part of further research into a possible link between XMRV and ME/CFS is to retest anyone who has sent blood to the US. This process would involve retesting at one of the retroviriology laboratories here in the UK that has been unable to find any evidence of XMRV in the blood samples they have analysed so far. We know that the UK research groups would be willing to do this retesting but this research can only move forward if people are willing to volunteer. The MEA Ramsay Research Fund is willing to assist with the funding of this research.
We have also indicated that all the research groups that have published positive and negative findings on XMRV so far should now test a new cohort of mutually agreed ME/CFS patients. We will then know whether there is agreement or disagreement when blood samples from the same cohort of people with ME/CFS are simultaneously tested. The MEA Ramsay Research Fund would again be willing to help fund a well designed study.
Blood donation and XMRV status
The ME Association has written to Sir Liam Donaldson, the Chief Medical Officer, to ask him to reconsider the current advice on blood donation and ME/CFS so that people with a past history of ME/CFS are also excluded from donating blood. The position, at present, remains unchanged in that people with ME/CFS should not donate blood until they have fully recovered. This official advice goes back some time and is not related to XMRV.
Summary of current advice regarding blood donation can be found here:
Most recent statement on the blood donation situation in Canada:
Possible consequences of being XMRV +ve
We have been asked whether insurance companies and others will be placing restrictions on people who are XMRV +ve in the way that this sort of discrimination can take place with people who are HIV+ve. At present, we are not aware of any insurance companies that have introduced any such restrictions, or are intending to do so in the near future. But this is clearly something people will need to think about if they are considering having an XMRV blood test. Remember the relevant question may be whether you have been tested for HIV (or XMRV) and not whether the result is in your medical notes.
It should also be noted that the exact mode of transmission of this retrovirus remains uncertain. If XMRV does turn out to be a disease causing virus similar to HIV, and can be transmitted in a similar way through body fluids, then people who turn out to be XMRV+ will obviously have to take the same precautions in relation to lifestyle, sexual relations etc that apply to HIV. They will also have to cope with some of the restrictions that may occur as a result.
MEA website poll on XMRV
The April MEA website poll is assessing public opinion on XMRV.
Dr Charles Shepherd
Hon Medical Adviser, ME Association