Science Interviews


Tue, 9th Jun 2015

Donating blood

Jacob Grinfeld, Cambridge Stem Cell Institute

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Around one in four of us will need a blood transfusion at some point in our lives, yet Blood Donation Stickeronly 4% of us regularly donate. But why is there this demand for blood in the first place, and how does the donation process work? Georgia Mills accompanied blood specialist - or haematologist - Jacob Grinfeld to the Cambridge Blood Donation Centre to explore blood groups and try her first donation...

Georgia - Right now, blood is coursing through your veins and arteries. Itís transferring oxygen to your tissues and organs, and helping you to fight off infections. Your body is constantly replenishing your blood but due to illness and accidents, around 25 per cent of us will need to top up at some point in our lives. For this, we need someone else to donate theirs. To find out more about blood donation and to try and perform my social duty, I took a visit to Cambridge Donor Centre. There, I met haematologist Jacob Grinfeld who told me a little bit more about what it was that people were giving away.

Jacob - Broadly speaking, blood has 4 main constituents. There's 3 different sorts of cells and then there's the plasma which is the fluid that they swim in. Red blood cells give blood its red colour and they contain haemoglobin which carries oxygen throughout the body. There's various sorts of white blood cells but effectively, their job is to fight infection. Platelets are tiny cells that are involved in clotting the blood. The plasma transports lots and lots of different proteins, sugars, nutrients, and also carbon dioxide.

Georgia - Something you hear people say a lot about blood is theyíve got a specific blood type. What does this mean?

Jacob - What people are generally referring to are the ABO blood groups which refer to proteins on the surface of the red blood cells. There's 2 main proteins there, there's A proteins and B proteins. So, you can either have all Aís, all Bís, a combination of the two which gives you AB or you can have neither which means you have O blood.

Georgia - So, why does your blood type affect who you can and can't give your blood to?

Jacob - Everyone develops antibodies to the A and B groups. If you donít have either of them then you have antibodies to both A and B. If you lack A or B then you have antibodies to that specific group. This is important because if you give blood to someone who has antibodies against that blood, they immediately have a very dramatic reaction to that.

Georgia - These proteins on the blood cells act as sign posts. If the blood has a sign post that isnít recognised, things called antibodies go on the offensive, much the same way they would if a virus had invaded the bloodstream.

Jacob - So, what this means is group O blood is the best to give because it doesnít have any A or B proteins on the surface. You can give it to anybody which is why itís very important for hospitals to have a stock of O negative blood. So, in emergency situations, when you donít know what blood group a patient is, you're pretty much guaranteed that you can give them O negative blood.

Georgia - At the start of each donation, you fill out a health check and then get the iron levels in your blood checked via a simple finger prick test. If there's enough iron in your blood, it sinks to the bottom of a small test tube.

Donation assistant - This is where it would start sinking.

Georgia - We want it to sink.

Donation assistant - We do.

Georgia - Oh no, itís not sinking.

Donation assistant - And it hasnít unfortunately. So, itís just floated back up to the top.

Georgia - As you heard, I failed that test but my producer Heather passed with flying colours so I joined her in the donation hall.

Heather - Ready. Itís going in. Itís going to go in now. Itís just like a little pinch.

Georgia - So, I can see theyíve got this little blood bag. Is this is your blood?

Heather - I hope so.

Georgia - It looks like there's already a liquid in the bag. What is this?

Jacob - Thatís citrate which is an anticoagulant.

Georgia - Why is this important?

Jacob - So that you could get the blood back out of the bag and itís not all clumped and in a lump.

Georgia - So, how are you feeling Heather?

Heather - Yeah, fine. This chair is really comfortable.

Georgia - Each donation takes under 15 minutes with some people being done in 4, but whatever the time, when you're done, there is a reward.

Heather, I see you're having your celebratory biscuit. How are you doing?

Heather - I'm really good. This biscuit is really nice.

Georgia - I wasnít allowed to give so I donít think I'm allowed one of these biscuits.

Heather - I asked and they said itís fine.

Georgia - Brilliant! I'm cheating the system.

While we ate our biscuits, some of them not quite earned, we met first time donor Anna.

How did it go?

Anna - Yeah. It was fine. I was really worried about the actual giving blood there but then that bit was easy. All the nurses were really, really friendly.

Georgia - Would you do it again?

Anna - Yeah. I feel really proud of myself. I've achieved something today.

Georgia - Heather and Anna were just two of the donors there last week. But I wanted to know what their blood will be used for.

Jacob - When we take the blood we actually break it down into its components. So, we can get from it red cells, platelets and proteins from the plasma. We use red cells for patients who have lost blood or can't make enough blood themselves. Similarly, we can give platelets for patients who have low platelet counts and therefore, have problems with blood clotting. Also, we use plasma which contains a lot of clotting proteins as well to correct problems with clotting.

Georgia - Can blood be used if someone has say, an accident on the road?

Jacob - Yes. So, thatís obviously a source where blood will be in demand, people that have lost a lot of blood from accidents. As I mentioned before, thatís where itís important to have a stock of O negative blood.

Georgia - But itís not just the rare O negative blood types that doctors are on the hunt for.

Jacob - In particular in Addenbrookeís, we have a lot of cancer patients and also do a lot of complex surgery including multi-organ transplants. So, there's a high demand for a range of different blood products. Currently, only 4 per cent of the eligible donor population in the UK are actually giving blood. So, weíre always on the lookout for more new donors.

Georgia - Hopefully, that will be next time. I will donate in the future Iíve been given a little pamphlet and I'm going to eat spinach and kale and in 3 monthsí time, I'm going to give it another go.

Chris - I thought you're going to say "some iron supplements".

Georgia - I think there's a lot of iron in spinach, I was told.

Chris - But is it available because thatís the point, isnít it? Lots of foods have got lots of iron in them but itís not in the form that you can readily absorb.

Georgia - I see. Apparently, as well, cups of tea inhibit your ability to absorb iron which I think might have been my problem. I overdose on tea daily.

Chris - Orange juice puts iron into a form which is efficiently absorbed. So, drinking a glass of orange juice with your spinach or whatever your source of iron is, your black pudding whatever you're going to eat. This increases the uptake in the gut. Thatís the best way to do it, actually. So, up your vitamin C intake because it keeps it in the form - in the un-oxidised state - that means it can be better absorbed.


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