14 June 2012 Last updated at 11:29 ET

Article written by Fergus Walsh Medical correspondent

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Appeal for blood donors before the Olympics

 

Greater stocks are needed for the Olympics

Are you a lapsed blood donor? If so, what has stopped you donating? We are creatures of habit and it seems any change in our routine can get us out of the habit of giving blood.

Bad weather clearly affects stocks as donors struggle to reach appointments. But major sporting occasions - even national celebrations - can dent donations.

During the 2006 World Cup there was a 20% fall in donations. NHS Blood and Transplant is concerned there could be an even bigger fall during the Olympics. So it's launched an appeal for donors - with the aim of increasing stocks by 30% before the opening ceremony on 27th July.

All blood types are required to build stocks, but there is a particular need for O-donors.

O-blood can be given to any patient regardless of their blood type. More than a million visitors from all over the world are expected in London, whose blood type may not be known. So should they need a transfusion, O-blood will be needed.

Blood's journey from donor to recipient

There are nearly 2.5m eligible people who have O-blood, but just 140,000 are donors - a figure which has declined sharply in recent years.

It's stating the obvious but donations save lives, like that of five-year-old Hannah Farrands.

She has had five major heart operations and required blood transfusions each time.

Hannah is now well thanks to her treatment. I met her and her mum at a blood donation session outside the Tower of London. Helen Farrands said: "Without donors Hannah would not be here - it's as simple as that. So please give blood."

You can see a brief interview with Helen in the video above and get some more information about the need for donations.....and you can see how easy it is to get blood out of a medical correspondent.

If you want to contact NHS Blood and Transplant to book a donation then you can visit their website.