OATS records are regionally based payments for treatment within the UK. These differ from Extra Contractual Referrals (ECR's), which were health authority based. Under ECR's a re-charge occurred when a Welsh Patient was treated in another Welsh Health Authority Area. This is not the case for OATs', where charging is inter-regional.
OATs may also be elective, but permission for payment to a Trust by the residents Local Health Board must be in place first.