EVERYONE should be legally required to register for or against organ donation in their lifetime to reduce the risk of bereaved relatives vetoing potential transplants, researchers have said.

A study concluded that a two-way registration system would be more effective at ensuring a person’s wishes are respected after death.

The researchers also warned that opt-out regimes of the kind due to be rolled out in Scotland do not guarantee an increase in transplant rates because they are more likely to increase the incidence of families refusing consent because they are unsure whether their loved one genuinely wanted to be an organ donor.

In the first study of its kind, psychologists at Queen Mary University in London presented nearly 1300 participants in Europe and the United States with a fictional scenario where they had to judge whether it was a person's "true wish" to donate their organs, given that they were registered to donate.

They found that participants were notably less likely to believe this in an opt-out scenario.

Co-author Dr Magda Osman said: "If you have an organ donation register that presumes consent, then it is harder for a third party to tell if you being on the register reflects what you genuinely intended.

"As it is, family veto rates are high in systems where there is an opt-in system, so by implication, our findings suggest that veto rates would certainly not fall as a result of introducing an opt-out system, if anything it would create greater problems, particularly ethical ones."

The study also found that only 19% of participants living in a country with an opt-out system realised this was the case, compared to around 44% of those who could correctly identify that theirs was an opt-in system.

The study adds: "If families are unaware that a default opt-out system has been implemented then the families are equally likely to believe that the deceased was also unaware of such a system and may have forgotten to record an objection in his/her lifetime."

The authors said this emphasised the importance of educational campaigns prior to the introduction of a new organ donation system.

However, they conclude that a "mandated choice" system would be the best at eliminating any doubt over a deceased person's true wishes.

They state: "We recommend a two-way register. This means there is the option to register for both intentions...an example of this is a mandated choice system introduced in our study which makes it a legal requirement that everyone must register their intention to donate or objection to donate during their lifetime...it ensures one's preference is respected."

Plans are underway to replace Scotland's current opt-in system with a "presumed consent" model which would make all eligible adults living in Scotland organ donors by default.

Individuals can withdraw their names from the donor list if they object, and relatives are still entitled to refuse consent even if the deceased did not opt out.

NHS Blood and Transplant reported in 2016 that 547 families across the UK had blocked organ donations since April 2010 despite being informed that their relative was on the opt-in donor register.

This translated into an estimated 1,200 people missing out on potential life-saving transplants.

Currently only 46% of the population in Scotland is signed up to the donor register.

Wales already has opt-out, as do countries including France, Germany, Norway, Finland and Singapore.

However, while opt-out laws do increase the number of registered donors it is unclear whether that necessarily leads to an actual rise in transplants.

Where a spike in transplants has occurred, researchers stress that other factors - such as an increase in transplant funding or education campaigns - may be at play.

Dr Osman said: "Even if you automatically default everyone in the population onto an organ donation register, that will make no difference if legally, ultimately families have the right to veto that decision, and secondly if you don’t have the infrastructure in place to carry out organ transplants."

The study is published today [Thu] in the 'Journal of Experimental Psychology: Applied'.