NHS BT send through a list of identifiers from their database once a quarter (End of January, April, Jul, October) This file is matched with the UKRR database and the matched list is returned to NHSBT who then return the transplant data on the matched patients. The matching process is not straight forward and the current code base is slow. NHSBT usually raise queries which have to be sorted before the final data is sent through. The supplied data is saved into the UKRR database.
Process Documentation
JIRA