Stocks of one of the most important blood groups are down to just four days.
Ideally the Scottish Blood Transfusion service hopes to maintain at least six days stock of each blood group.
However, levels for O- are down to just four days.
Stocks of this blood group are vital for use in emergencies as it can be given to almost every patient.
Around 9.5% of the population in Scotland have this blood type.
As each donation can be split into three parts, each time a person gives blood they are potentially saving or improving the lives of three people/