Clinical geneticist Professor Sir John Burn told GPs at the 2014 RCGP annual conference in Liverpool that the breakthrough could transform prescribing in primary care, as point-of-care DNA testing becomes cheaper and more convenient.
Professor Burn, from Newcastle University, said it was now possible to test a patient’s genetic sensitivity to warfarin within 20 minutes for just £20, and the technology could soon be available in primary care.
The same machine will let the GP know the correct dose of warfarin for a patient.
Professor Burn said this would greatly improve outcomes. ‘It’s like saying, don’t buy shoes until you know what size your feet are. You wouldn’t just take away a size seven and hope it fits,’ he said.
‘There are two genes involved in warfarin metabolism. We know that there are three very common variants [of these genes] in our population. If you test for those three variants, you can accurately predict people’s [required] dosage.’
Recent NICE guidance for AF recommended wider use of novel oral anticoagulants (NOACs) as alternatives to warfarin, which requires regular monitoring and is difficult to dose correctly.,/p>
But there are fears this is driving up NHS spending, as these treatments are estimated to cost more than three times the price of warfarin.
‘We can't afford to put everyone on NOACs and we don’t need to,’ said Professor Burn. ‘What we’re trying to do is demonstrate that warfarin can continue to be used if you genotype people.’
Professor Burn and his team have started to roll a scheme to trial point-of-care testing and genotype-led dosage adjustment in Newcastle.