BLOOD TESTS ∙ 4 minutes read

5 things you should know about giving blood

By Joseph Lee | Medically reviewed by Dr Jaskirt Matharu

We’ve come a long way in our understanding of blood since British physician, William Harvey, first discovered how blood circulates inside a living body almost 400 years ago. 

But it wasn’t until 1946 that the National Blood Transfusion Service was set up in the UK.

The National Blood Transfusion Service transformed the availability of blood for surgical procedures by providing a national bank of blood. Having a nationalised stock of the red stuff helps to save lives through blood transplant or blood transfusion, the main benefit of giving blood.

There were less than 200,000 blood donations collected in 1946, but thanks to a better understanding of the benefits of blood donation, as well as advancements in medical technology, around 1.6 million blood donations were collected in 2016 in the UK.

Taking your blood is so easy now, you can do it in the comfort of your own living room with an at-home blood test. But if you want your blood extraction to help others, there’s plenty of blood inside you to give away. 

The average healthy adult has around nine pints of blood inside them. During a standard blood donation, around a pint of blood (470ml to be precise) is taken from the body. So, if you are interested in donating your blood to a blood bank in the UK, here’s a few things you ought to know:

1. Most people can do it  

If you are wondering how long blood donation takes, it’s over quite quickly, with the average blood donation duration taking around 5-10 minutes, depending on individual blood flow speed. 

If you are a fit and healthy individual you should consider giving blood because pretty much anyone can do it. In the UK, people between the ages of 17 and 66 and weighing between 50kg and 158kg can give blood.

People over the age of 70 can give blood if they are regular donors and have made a full blood donation within the last two years.

People must never donate if they are carrying diseases such as hepatitis B or C, or have ever injected a drug. People who are HIV positive or receiving HIV treatment must also never donate blood. 

Up until recently in the UK, gay and bisexual men had heavy restrictions put in place on the frequency they could donate blood. In June 2021, a new blood donation policy was passed to allow gay and bisexual men to donate blood without any waiting periods, provided they follow other, less stringent rules.

2. Your blood matters

There are 4 main types of blood which are categorised into the blood groups, A, B, AB and O. Each of these main blood groups can be either RhD positive or RhD negative, meaning there are 8 blood groups in total.

There is no right or wrong type of blood, however, particular blood types are more in need than others.

Young blood is needed to help save future generations, as half of all blood donations in the UK come from people who are over 45 years old.

But it is not just the age of blood donors that is in the spotlight. Blood donors of multiple ethnicities such as black and south Asian blood donors are in need.

The blood type Ro is a subtype variation of the RhD positive blood type and is more common in people of Black heritage. Demand for Ro increases by 10-15% each year in the UK, yet only 2% of regular donors have this blood type.

3. Men can do it more often than women 

Men can give blood more regularly than women. So guys, there’s no excuse!

Male donors are required to wait for a minimum of 12 weeks between full blood donations, whereas females have to wait 16 weeks.

So, why do women have to wait an extra 4 weeks?

Despite a human’s bone marrow producing around 2-3 million red blood cells and releasing them into circulation every second, it can take a few weeks for an adult’s red blood cells to be fully replaced.

During blood donation, whether it’s from a male or a female, some of the haemoglobin in red blood cells is lost. Haemoglobin plays a vital role in transporting oxygen to tissues around the body. Haemoglobin also contains iron and when this is depleted during a blood donation our bodies take it from our store of iron. 

Men normally have more iron stores than women, which is why they can donate blood more frequently. 

Don’t worry though fellas, your blood won’t go to waste. Blood lasts several weeks once it has been extracted. When mixed with additives, red blood cells can be kept and used for up to 35 days in the UK, whereas in Germany it’s up to 49 days.

4. You should tense your butt 

Clench your buttocks when you go for a blood test. No, not because you are scared of the procedure but because the blood bank staff might ask you to.

It is normal to feel nervous if you donate blood, especially for the first time. But blood donation banks in the UK have a novel way of making you at ease, by asking you to tense your butt cheeks.

Apart from enabling you to focus your mind on another part of your body, away from a needle in the crook of your arm, this request is based on a scientific theory. 

Applied Muscle Tension (AMT) is a basic technique that supports and maintains blood pressure, stopping donors from feeling light-headed or queasy. Tensing large muscle groups such as the gluteus maximus is probably not what you imagined as part of your blood test… you might even get a biscuit from staff after you’ve finished your donation as well!

5. Leeches are used to take blood…

Yes, this one might be hard to believe. Leeches are used to this day in the extraction of blood.

But if you are heading down to your local blood donation bank, you aren’t likely to find a jar of blood-sucking leeches ready to chomp on you. 

Leeches are mainly used medically in plastic surgery, where they can be effective in draining swollen tissue after an operation.

A bite from a bloodsucking leech contains its own anaesthetic, which means it’s painless to humans.

The bottom line

Giving blood is literally giving the gift of life. Most fit and healthy people can give blood and men are able to give blood more often than women. Some blood groups are less common than others and people who carry these blood types are especially encouraged to donate. There are over 2,000 blood donation clinics in the UK - you can find places to give blood near to where you live here.

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