Figures obtained under Freedom of Information rules show 35% of 5,548 GP referrals received by a referral management centre commissioned by NHS Vale of York CCG in 2013/14 were returned to practices.
The Referral Support Service sent back 14.4% of referrals because they lacked certain information or attachments, while in 12.5% of cases GPs were told to treat the patient in primary care instead.
The finding emerged as part of a wider GP investigation into the rise of referral management centres under CCGs. This found errors by these centres have delayed care and breached confidentiality in the past year, although no such errors were made by the Referral Support Service in NHS Vale of York CCG.
Our figures suggest the average rate of return for GP referrals by referral management centres across England was 4.4% in 2013/14.
CCGs are increasingly resorting to referral management schemes to manage demand on stretched acute services and to shift care into the community.
The CCG spent £211,404 on its referral management centre in 2013/14, which is run by the North Yorkshire and Humber Commissioning Support Unit and began operating in October 2013.
At the same time as a third of GP referrals were being rejected, the service saw a 20% drop in approved referrals sent to triaged specialities, including dermatology, ENT, general surgery, and gynaecology.
The CCG has since increased funding for the programme to £408,000 in 2014/15, and is targeting an 8% reduction in referrals over the long-term.
Board papers from a CCG meeting held in March 2014 reveal there were 'a small number of "teething problems" for some GPs'.
A CCG spokeswoman said the referral return rate was high in 2013/14 because GPs were 'getting used to the process and the referral guidelines associated with it'.
She added: 'We are now a couple [of] months into implementation and the return rate has reduced to 19%. Our expectation is that once the Referral Support Service becomes well-established the return rate will be no more than 8%.'
She said the aim of returning referrals was to be 'supportive' of GPs, and that the scheme offered advice and guidance on treatment that can be offered in primary care instead.
Responding to the overall findings of the GP investigation, GPC chairman Dr Chaand Nagpaul said: 'We need to have an approach of targeting and facilitating improved referral decisions, rather than an approach of creating obstacles and delays.'
Referral management centres? We need a Centre for the Self-Improvement of Referral Decisions [Inside Commissioning]
Guidance on working with referral management centres [Medeconomics]