18 July - Bloodletting day
It's our annual bloodletting day in the office,
unfortunately I did not pass the screening due to a recent trip abroad.
Better luck next year :P
BTW, my blood type is AB :)
Red blood cell compatibility
* Blood group AB individuals have both A and B antigens on the surface of their RBCs,
and their blood serum does not contain any antibodies against either A or B antigen.
Therefore, an individual with type AB blood can receive blood from any group (with AB being preferable),
but can donate blood only to another group AB individual.

Universal donors and universal recipients
With regard to transfusions of whole blood or packed red blood cells,
individuals with type O negative blood are often called universal donors,
and those with type AB positive blood are called universal recipients