Blood supplies in American have hit such low levels that 40 cities have had to postpone operations. It is the greatest shortage of blood in the US since the Second World War.
Blood banks are down to reserves of less than a day's supply, although they normally aim to keep enough for a week's transfusions.
The severe shortage has been caused by a combination of factors. Demand has risen recently, most notably following the Los Angeles earthquake, while fewer people are prepared to give blood.
Experts reckon that supplies could have been exhausted had the quake happened later in the day, and so caused more injuries.
Many fear that they may become infected with HIV, which has also fueled the trend for autologous blood donations, where a donor deposits blood exclusively for his own use.
Other factors include the recent cold winter in the US, which may have reduced the turnout at blood centres, and an outbreak of flu, which has reduced the numbers of healthy donors. The recession has also taken its toll, with fewer workers left to donate their blood as part of company blood drives.
The blood banks themselves have also been throwing away supplies of blood, so fearful are they of a lawsuit for supplying contaminated blood.
Britain's blood supplies have also been understocked for over a year. The cause has been an increase in operations which has outpaced the rise in the amount of blood given. To try to counter this, the Department of Health has launched a lb250,000 newspaper advertising campaign to attract more donors.
EC countries have been asked to adopt US standards for plasma handling. The call has come from the International Plasma Products Industry Association which describes the US system, regulated by the Food and Drug Administration, as being the only safe one in the world.