Although the TTC and two of three SCTCs perform extended phenotyping (beyond ABO/Rh(D), C/c, E/e and K) for non‐alloimmunised TDT and SCD patients, only 10% of non‐TTCs/non‐SCTCs perform upfront extended phenotyping for all TDT/SCD patients. Here, ABO is linked to Schnyder corneal dystrophy.