Not sure about the identifier used in England and Wales, but in Scotland most boards use the 10-digit CHI number. From this you can determine the patient's dat

Not sure about the identifier used in England and Wales, but in Scotland most boards use the 10-digit CHI number. From this you can determine the patient's date of birth and sex. For this reason it is not used as a patient identifier for information visible beyond staff cleared to view this personal information. Either data is aggregated to a point where it's not individually identifiable or an anonymised ID is used, and the most distinctive fields removed. I hope that's what's happening here!