A British study has found an opt-out organ donation register may not increase the number of donations.

The researchers say an opt-out system automatically registers everyone and presumes consent to donate, whereas an opt-in system requires explicit consent to donate and indicates willingness.

Most organ donation legislation, whether opt-in or out, includes a clause that allows the final decision to donate to be made by family members.

So, the experts say donors should actively choose to be on the register by opting-in to ensure they genuinely want to donate their organs and to limit families from refusing the donation of their deceased relatives’ organs.

Plans to introduce an opt-out system in England by 2020 have recently been announced by the government, but the researchers suggest this will create ambiguity and will not reduce veto rates.

In their new report, researchers at Queen Mary University used participants from countries that have either a default opt-in or default opt-out system.

They were presented with a fictional scenario and asked to take on the role of a third party to judge the likelihood that an individual’s ‘true wish’ was to actually donate their organs, given that they were registered to donate.

They found “it’s harder to judge the underlying wishes of the deceased if they were on an opt-out and mandatory donation register”, according to lead author Dr Magda Osman.

“Making a free choice indicates what your preference is. If you don't actively choose and you are listed as a donor on the register, then it isn't clear if you really wanted to donate your organs,” she said.

“This matters because if in the event of death your relatives have to decide what to do, they may veto the organ donation if they can't tell for sure what your underlying wishes were.”

Dr Osman said additional techniques could be used to boost the rate of donation if simply changing to an opt-out system does not.

“To help increase actual rates of organ donation, we need more transplant coordinators working with families to help them understand the issues before being faced with a monumental and distressing decision,” she said.

“We also need to offer people a way to indicate explicitly what they wish to do.

“This should involve an expressed statement of intention if their wish is to donate, or an expressed statement of intention if there is an objection to donate. This reduces the ambiguity in trying to infer what one wanted to do when it comes to donating their organs.”

The study is accessible here.