I've been a blood donor since I first went off to university, although I had a gap for a couple of years after I left Durham, before I got settled in London. Anyway, I've done 18 donations so far, of the usual type: I turn up, they stick a needle in my arm, and pull out about a pint of blood, which they go off and do things with. I do that about three times a year, and it takes about half an hour (about 15 minutes for the actual donation, and another 15 minutes of hanging around before/after).
An alternative is apheresis, where they collect platelets. I'm not an expert on the detailed medical aspects, but the basic idea is that you get needles stuck into both arms at once. They then pull blood out of one arm, take out some platelets, and put the blood back into the other arm. This takes about an hour and a half (about two hours when you include hanging around time), and it can be done every two weeks, since the platelets get regenerated a lot more quickly than the red blood cells. About 60% of donors are capable of giving platelets (there are a few extra criteria, e.g. "never having fainted while donating"), but I don't think anywhere near that proportion of people actually do it. I think that's partly because of the extra time commitment, and also partly because of the travelling involved. With regular donations, they have travelling units (either a bus or setting up in a hall), and some bigger companies will get them to come into the office. By contrast, the apheresis involves pretty big machines, so you have to go to them.
I first heard about this a few years ago, in the newsletter/magazine thing that they send out to donors, and I figured that it would be worth doing; this was during my MSc, so I had a relatively flexible timetable. However, I was a bit put off by the lack of enthusiasm I got. Basically, I asked about it the next time I went to a regular donor session, and the staff just said "You can't do it here, so you'll need to find a permanent unit that does it". I can understand why they couldn't do it, but I was expecting a response like "Wow, that's great; here's the address of the nearest unit." Or "Give me your details, and we'll get someone to call you to set up an appointment". As it was, my volunteering spirit only went so far, so I never bothered to track down the relevant address myself.
Then I had a letter through a couple of weeks ago, asking me to join a "Baby Platelet" Panel in Tooting. This is platelet donation, but it's specifically set up for very ill newborn babies and infants. Since babies are so much smaller, one donation can do twelve of them. However, only about 2% of donors are actually able to do this (something to do with antigens). Apparently I'm on the shortlist for this compatibility, so I went along this morning to get tested. They took a blood sample (I'll hear back in a couple of weeks), and also did some testing for blood pressure, and ease of access to veins. I normally donate from my left arm (being right-handed), but apparently the veins on my right arm are "better" for this (more prominent or something). Since I mainly type rather than write nowadays, I guess it doesn't make too much difference.
So, now to wait and see. I have a reasonable amount of flexibility in my working hours (my standard trade-off that I get lie-ins and then work on the servers when lots of people have gone home), so I think that I can fit this in. I wouldn't like to say that babies are "more deserving" than adults when it comes to blood transfusions, but it does feel better. When I did some self analysis a few years ago (when admittedly I was feeling a bit gloomy), the fact that one of my flatmates was doing research to help blind babies almost seemed over the top in the "good deeds" stakes ("for my encore, I shall save some nuns from that burning building..."). I don't have the same frustration at my new job, but I do think that this would be a good thing to do; an effective way to make a difference.