Why don't we take blood from dead people?

It would sure be a whole lot easier if we could.

A while ago my 9 year old godson turned to me and asked me why dead people can't donate blood like they can donate organs. He reasoned that since there's a shortage of blood donors, it would be a great solution. Though I agree with him it would be a great solution, donating blood from deceased people really is quite complicated.

First off, there's the ethical question. You'd need consent just like with donating an organ, you cannot just 'take' blood from dead people. This of course could be solved quite easily by adding another box to your donor card saying that you allow your blood to be donated. There are however other reasons why we can't just 'take' blood from deceased people.

Eligibility

Not everyone who fills out a donor card is eligible to be a donor candidate. Perhaps there's something in your blood, a deficiency perhaps, that would make your blood not eligible for donating. If you've ever donated blood you'll that this is always a possibility. If you're too young, too old, if you're pregnant or just had a tattoo; in all these cases you are not eligible to donate blood. This of course goes for deceased persons as well. The blood could also be riddled with viruses, germs, medications or poisons, all depending on how the person died to begin with.

There's a time limit

Blood doesn't keep. There would be a very short window of opportunity to collect blood from a deceased person, because very quickly the blood starts to clot. It also becomes loaded with waste products - such as carbon dioxide and lactic acid - which normally would be pumped around your body, but stays put as soon as you pass on.

It's easier and less time consuming to donate 'live' blood

Even if the blood from a deceased person can be extracted and used on time, and even if the blood is eligible for donating, there's too much fuss to do it. A living person who is eligible as a blood donor can donate time and time again, while a deceased person of course can only do it once. The donated blood also needs to be throughly screened and processed before it can be used, something you don't really have time for with blood from a deceased person.

Yes there is a blood shortage world wide, but it would be much easier (and cheaper) to invest in getting people to donate blood voluntarily at a blood bank or during a blood drive. If you want to know how you can donate blood click on one of the following links:
American Red Cross
National Blood Service UK
Sanquin Netherlands
Etablissement Français du Sang [French National Blood Service] 
Canadian Blood Services
Australian Red Cross

NB: It's impossible to list the blood services for every country world wide, just check at your local hospital to see how you can help.