Table 2

Scenarios involving different combinations of patient identifiers that resulted in missed matches (where sex and date of birth match)

SexDate of birthNHS numberHospitalLocal IDPostcodeMissed matches (% of 3609)
Scenarios where NHS number differs and postcode differs
 110110840 (23.3)
 11010043 (1.2)
 11001033 (0.9)
 110000316 (8.8)=1232 (34.1%)
Scenarios where NHS number differs and postcode is the same
 11011115 (0.4)
 11010117 (0.5)
 1100015 (0.1)=37 (1%)
Other scenarios (see online supplementary table S1)=2340 (64.8%)
  • NHS. National Health Service.