I did it for the chocolate

I’ve become the annoying person who must tell the world that they’ve donated blood

Yaning Wu
5 min readAug 4, 2021

This Monday, I booked a spontaneous appointment in London to give a pint of my blood to whoever was in need. It was much more fun than I thought it would be, so I decided to document the journey through dataviz.

Alt text is given below the images.

Slide 1

I did it for the chocolate: I’ve become the annoying person in your life who donates blood and has to tell the world. Here’s what my experience was like. (I hope you’ll join me next time.)

[An illustration of a mint Club chocolate bar]

Slide 2

I think I’m a fainter. I faint before hospital appointments, after hospital appointments, after standing up too long, because it’s too hot outside … You get it. But donating blood has always been a goal of mine. After realising I had a whole week off work due to haphazard scheduling, I booked an appointment to donate in a part of town that I always enjoyed visiting. It was time to do a small thing that terrified me, and I couldn’t bring anyone along in case I actually passed out. I couldn’t imagine how embarrassing that would be. Besides, I knew that I wouldn’t be allowed to go through the process if I was medically ineligible.

Here’s some basic information.

The human body contains roughly 10 pints (5.7L) of blood. In the UK, less than one-tenth of this amount, 470mL, is taken during each donation. There are certain age and medical barriers to becoming a donor, which you can check online before registering. Most people, however, are eligible. The majority of current UK donors are middle-aged or older.

[A 90% filled bar chart with backdrop of medical tape used in actual donation]

Slide 3

After arriving at the donor centre, I answered some questions about my medical history while downing half a litre of isotonic fruit-flavoured water. Known for my sloth-like drinking habits, I was dreading this sudden intake, but the sugar helped. I then took a prick to my finger to make sure my haemoglobin levels were high enough to donate safely.

[Illustrations of a pink liquid in a cup, a paper form, and a ballpoint pen]

With both tests passed, I slid into a donation chair with the grace of a just-caught trout.

[An illustration of a blue donation chair used at the donor centre]

As I got ready for the needle, I was disappointed to learn that my veins were evading detection after several attempts to locate them. Luckily, this caused only a slight delay.

[A bar chart with one bar labelled “after rejection by Ivy Leagues” and another labelled “after having own veins deemed tiny”. The x-axis is “feelings of inadequacy”, and the first bar is slightly longer than the second]

Next, someone applied antiseptic to the crook of my elbow and spread it around, calling this a “vein massage”. I’ve never been so relaxed.

[A quadrant scatter chart showing that while conventional massages are moderately satisfying and quite pricey, a vein massage is basically free and very satisfying]

Slide 4

I faced away as the bag began to fill. To regulate my blood pressure, I was advised to clench and unclench my fists and squeeze my thigh muscles, which I found an unnerving exercise given the number of people tasked with monitoring me.

[A line chart depicting a sudden spike in the extent of my quad + glute workout during the donation session]

After less than ten minutes, it was over. I sat tight and was handed another half a litre of water, this time unsweetened. Then, I arrived at the moment I had waited for all this time: the selection of my post-heroics snack. I went for the iconic orange Club chocolate bar, which ended up being too sweet for my taste. What a pity — there were so many options I could have chosen.

[Scatter chart annotated with types of snacks available at the donor centre ranked by net weight. They included two types of Crawford’s biscuits, two flavours of Seabrooks crisps, sweet and salty popcorn (largest net weight), and orange and mint Club bars (smallest net weight)]

I got up to leave with an indignant bladder, a bandage covering the donation site, and a slightly smarting right hand index finger.

[Image of cartoon bladder with angry eyes]

[Photograph of bandage over donation site]

Slide 5

I walked out of the donor centre with a sticker and instructions on staying well after the procedure. My pint of whole blood could treat up to three individuals, including people involved in accidents, receiving surgery, giving birth, or living with terminal conditions.

[Images of three stick figures: one pregnant, one walking on crutches, and one wheelchair user]

In many ways, giving blood is the epitome of privilege — doing so required me to have the time, energy, and resources to travel to an appointment, and of course, the good health to donate in the first place. I don’t have the STEM aptitude to become a doctor, so I was lucky that this life-saving avenue was available to me.

That’s how I feel, two days after — like the luckiest person alive. My donation site feels normal; in fact, my index finger has retained the more visible scar. By some masterful coincidence, the next date when I’m eligible to donate is my birthday. Would you like to come celebrate with me?

[Image of a sticker saying “Be nice to me, I gave blood today” with the NHS Blood and Transplant logo]

Source: NHS Blood and Transplant

Please ask your doctor about your eligibility for donation. This is only my personal experience.

To donate blood in England, visit this website!


I created these slides exclusively with Autodesk Sketchbook, taking some photographs from my own experience and some inspiration from images available online. I used multiple layers for each slide and then compiled them using Canva.



Yaning Wu

she/her. Population Health student @ UCL. Perpetual dataviz nerd. Published on Towards Data Science and UX Collective.