At last night's session, the Donor Carer who was hooking me up looked at my form and said "Oh - I just need to get you a label." She popped off for a moment and returned with a brown luggage tag, as if I were an evacuee. It read: 'RO'.
She explained that this was a new system they were trying, and I had a component in my blood that made it suitable for people with sickle cell anaemia.
"So you're going to help someone with sickle cell!" she said, which made my evening.
At home, I found this news release, which explains things in more detail. Turns out I have the Rhesus subtype Ro, which is often a match for people with conditions requiring regular transfusions.
My blood group is A positive, the second most common type, so it's cool that I have a rare subtype, and that from now on I'll know where my donation is most likely heading.
Another neat thing. Usually, when the donation is over I ask if I can stay lying down for a few minutes, because I have a horror of passing out. This time, however, I happened to have been looking at the CBT book on my Kindle while I was waiting to be called, in the section on safety behaviours and why you should challenge them. So when the nurse flipped my chair upright I just went with it, and it was fine. Suspect remaining in a reclining position was just contributing to the fear, and wandering off to get my lemon squash and prawn cocktail crisps is a much better course of action.