Blood donation (Photo)

Someone gives blood on campus in the UCC, Feb. 27, 2019.

It’s not hard to understand why most people prefer to keep their blood inside their bodies.

From needles to fainting, there are obvious reasons to steer clear of donating, right? However, so much of what students believe in regard to the process is based on a lack of information. What really goes on when you donate? What happens to your body? And is all the premeditated worry even necessary?

The process

As Kristen Ungar, territory manager of London’s Canadian Blood Services branch, explains, there’s so much more hidden behind the veil of anxiety.

“The best thing to do first is to take our eligibility quiz online,” Ungar urges. “Many people think they’re not eligible to give blood, so they haven’t looked into the information correctly.”

To make things simple, the Canadian Blood Services eligibility quiz only takes a few minutes. Two main setbacks exist for students: travel and tattoos or piercings. If you’ve been outside of Canada or the continental United States in the past 12 months, you’ll be subject to extra questions. Any tattoos or piercings within the past three months will register you ineligible, but this criteria is updated constantly. It’s important to keep up-to-date (especially for students who travel) in case eligibility requirements change.

Once you arrive at the clinic, you’ll check in and fill out a screening questionnaire. The questionnaire touches on everything in the eligibility quiz, making sure you’re in well enough health and are able to donate. A screening associate or registered nurse will conduct a followup to further discuss any issues with the questionnaire.

"You want to be well hydrated, so drink lots of water and eat something in advance of your donation,” Ungar says.

You can expect to be seated for roughly five to 10 minutes minutes while actually giving blood. Some donors may experience slight fatigue, but as long as you’re in good health, have maintained an intake of water and have eaten prior to donating, you should have no issues.

To ensure proper recovery and as a precaution, you'll be asked to sit in a rest area following your donation. Here, there will be pop, juice, cookies and other snacks for donors to enjoy.

Post-donation, clinicians advise you take it easy; plan to exercise before you donate, steer clear of heavy lifting after, drive only if you are feeling well enough and, all in all, avoid strenuous activity. After that, your blood donation could be helping someone in a local hospital within three to five days.

Though needles yield an understandable fear, Ungar guarantees that they pose little risk.

"It's a very quick pinch when its going in. As long as you can handle the sight of blood and being around blood products and get over that fact, it's no issue," Ungar explains And for any last minute apprehension, staff at Canadian Blood Services are always eager to reassure and comfort donors throughout the process.

In Ungar’s own experience, deciding to give blood was a no-brainer. “Donating blood is an easy decision once you meet people that are blood recipients," she says. "I know several people in this community alone who receive blood transfusions on a regular basis to save their lives."

Ungar explains that in terms of donating, the torch is now being passed onto the younger generation as Canada’s current donor base ages and the regularity of their donations decreases; long-term donors are needed now more than ever.

The physiology

The process seems easy enough, but complex physiological questions still remain. How do our bodies react to having blood taken? How do blood types differ? Why are different types of blood more important than others? Even the location is worth questioning.

Vampires may be suckers for the neck, but blood operators favour the upper arm.

The field behind donating blood is extensive, but it's one that Dr. Peter Lesley, medical officer at Canadian Blood Services, is eager to discuss.

“It’s where the money is,” Lesley says. “There are great veins, readily accessible and acceptable to the donor as well.”

This position is the least invasive for the donor, as only an area of skin roughly three inches in diameter must be cleansed prior to the needle’s entry. The arm also provides easy access to veins, as well as an excellent pressure.

“The flow has to be adequate; there are obviously veins all over the body, but they don't often offer flow rates, certainly not that can be matched by the upper arm,” says Lesley.

The short period required for donation can be attributed to these high flow rates in the arm.

Once the needle has been inserted in your arm, half a litre of blood is drawn. This may seem intimidating, but the donor’s safety is always at the forefront. No more than 15 per cent of the donor’s total blood volume is removed; Lesley says this is a hard and fast rule that all blood operators adhere to.

Replenishment of this lost litre begins almost immediately.

“Ultimately, all blood is formed in your bone marrow; there are progenitor cells and stem cells there that differentiate into red blood cells, white blood cells and so forth,” Lesley reports.

As whole blood is drawn from the arm, our bodies become stimulated to produce new red blood cells from the bone marrow. Components formed in the marrow make their way from the bones into the bloodstream. In addition, stores in the spleen hold roughly 240 millilitres of red blood cells, nearly half of what is taken during donation. Think of this as an emergency stash that can kick into the circulation in times of shock or stress. Overall, red blood cells can take anywhere from a few days to a few weeks to be fully replenished.

But blood isn’t entirely comprised of red blood cells. Among other things is plasma, a fluid that is 98 per cent water, and replacing it is as simple as increasing your water intake.

“That replenishment process would take place over hours and at most maybe a day to reconstitute the two cups — or 500 millilitres — that we remove at a blood donation,” Lesley adds.

Despite the prompt replenishment, one of the largest misconceptions about giving blood is that faint, nauseous or light-headed reactions are to be expected following your donation. Lesley assures this is uncommon.

“Certainly, the majority of donors will not experience anything negative with respect to the donation and may in fact experience the more typical psychological surge of altruism and a feeling of great accomplishment that comes from donating blood," Lesley says.

Negative symptoms can be defined as a vasovagal reaction and are only experienced by between two and five per cent of donors.

The vagus nerve controls the responsiveness of the veins in the body. Therefore what happens to particular donors (especially if they’re at increased risk of fainting due to nervousness or apprehension as well as prior history) is that this nerve can become triggered, which will result in such symptoms as dizziness, nausea or pre-fainting (or presyncope in medical lingo). Though these reactions are quick to pass, more common symptoms include bruising at the puncture site or a some fatigue.

“We have many ways of reducing the risk of faints,” Lesley tells. “We now offer salty snacks and even make sure we have fluid volumes readily at hand. Donors are encouraged to consume two cups of water as they are working their way through the screening process.”

The consumption of salty snacks, such as pretzels, and a consistent intake of fluid before a donation can significantly reduce that two to five per cent risk of running into trouble with faint-like symptoms — and at Canadian Blood Services’ donor clinics, food and drink are offered for free.

Blood type breakdown

After leaving the clinic, you can expect to be mailed your official blood donor card as well as information on your blood type. The most familiar typing system uses A, B and O — but where do these letters come from?

Lesley explains that “we look for [A and B] antigens on the surface of the red blood cells.… If you have both, you’re an AB; if you have only A, then you’re A, or only B, then you’re B. If you have neither A nor B antigens, then you would be classified as an O.”

Blood is then further divided using the Rhesus blood group system by testing for the presence of what's known as the “D” protein or antigen. If this antigen is found on your red blood cells, you are positive, and a lack of the antigen means you're negative. Systems such as these allow for doctors to discern which type of blood is safe to give to a specific patient. 

The immunology of human beings has developed to keep one's blood distinct from others. This is a means of keeping your internal blood uncontaminated.

“If you were to, for instance, take someone’s blood who was type A and transfuse it into a patient who was type B,… there could be a very fierce immune reaction where the opposite of what’s on the red blood cells (being the antibodies that are floating around the red blood cells in the recipient) would identify that foreign red blood cells with the A antigen on it and destroy it,” says Lesley.

Type O negative is often described as the universal donor, as they have no antigens that antibodies are quick to attack. O negative donors are in demand as they aid in trauma cases where a recipient needs immediate care and their blood type cannot first be determined.

Your blood: Oxygen, plasma

Besides aiding in blood typing, red blood cells play a pivotal role in the human body.

“Red blood cells are crucial and unique in their ability to carry oxygen. It is the only cell that is adept at transporting oxygen … and providing oxygen delivery to our tissues,” Lesley declares. “Without oxygen, it's essentially a case of suffocation.”

If oxygen delivery were to cease, internal organs would shut down and shock would ensue. Lesley describes shock as “a complicated physiological state driven essentially by a lack of volume and a lack of oxygen delivery.” Red blood cells have the ability to correct oxygen delivery (specifically to injured tissues) as well as blood pressure, vessel volume and heart rate. Although transfusions are most often characterized by this need for red blood cells, some recipients require much more than that. Platelets, another component of blood, is most commonly used to prevent and stop bleeding.

“The classic recipient, though there are many different types of patients, would be a cancer patient who has low platelets as a side effect of the drugs and chemicals used to treat their cancer, so the platelet transfusion becomes life-saving,” Lesley explains.

Other examples include cardiac bypass patients who are vulnerable to a low platelet count and patients undergoing surgery who may require platelets and red blood cells. These transfusions can occur anywhere from several times a week, once following a trauma, or twice monthly in cases of cancer patients.

The final component regularly required by patients is plasma. This is the fluid or liquid within one's blood vessels which red blood cells are suspended in.

“We manufacture and collect off the plasma from the whole blood we take from the donors, and we put that into a bag and freeze it,” explains Lesley.

The classic scenario would include a trauma patient with excessive bleeding. These patients require the coagulation factors found in plasma. Burn victims may also require multiple units of plasma to be treated and resuscitated.

Value of donating

In each of these situations, blood donations are of the utmost importance. By keeping blood of all types easily accessible within local hospitals, it is thus ensured for use in potentially life-saving circumstances.

“We like to try and encourage our youngest members of society to start donating before life gets too busy,” Lesley says.

The commitment for donation is small; intervals are set at every 56 days for men and 84 days for women.

“That is in respect of the different physiology between men and women in terms of iron stores. It would take longer for the average female to recoup iron stores — this is a result of woman's unique iron needs and losses with respect to menstruation and childbirth, and also in body size,” Lesley explains. “I think they’ll find it a very straightforward process.”

Both Lesley and Ungar point out that, nowadays, donation is extremely accessible. You can go to, call 1-888-2-DONATE or download the GiveBlood app to set up a donation by appointment.

“Students are actually an incredible group of blood donors, and I find it the most positive part of my job working at Western University,” says Ungar.

For those hoping to donate, Canadian Blood Services provides monthly clinics at locations such as Citi Plaza, Oakridge Presbyterian Church, The Church of Saint Jude and their donor centre at 820 Wharncliffe Rd S.


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