> 1 unit of donated red blood cells contains about 2x1012 cells, and astronomers estimate there are only about 1011 stars in the Milky Way
> donated blood can be kept for up to 35 days
> only 4% of the people in the UK who are eligible to give blood are donors
> our bodies contain about five litres of blood – a total of about 20 – 30 trillion red blood cells
> more than two million units of blood are used each year in the UK
> blood costs about £140 per unit (roughly a pint)
> 95% of the population can be safely given O Rhesus negative (O-) bloodin an emergency
Mountford's team has managed to produce a billion red blood cells (109) or roughly a teaspoon from a single experiment. The number needed for trials is 1015, while commercial-scale production would be at least 1,000 times greater.