Less Wrong is a community blog devoted to refining the art of human rationality. Please visit our About page for more information.

Marius comments on Efficient Charity: Do Unto Others... - Less Wrong

130 Post author: Yvain 24 December 2010 09:26PM

You are viewing a comment permalink. View the original post to see all comments and the full post content.

Comments (318)

You are viewing a single comment's thread. Show more comments above.

Comment author: Marius 25 December 2010 05:49:32PM 9 points [-]

Your donations are not marginally useless! (unless you've been pregnant a couple times - in that case, consider stopping).

The reason for the discrepancies in donation rates between types A and B is both simple and complex: ethnicity. In the interests of safety (avoidance of Hepatitis C, HIV, etc) we've set up a system that subtly encourages certain types of donors and discourages others. The system is not racist per se, but it is most effective in obtaining donations from white, middle-aged, middle-class males.

Regarding signaling reasons: we are obviously very afraid of blood donated for signaling purposes. Accordingly, we do not allow people to donate to their relatives except under very unusual circumstances. Additionally, we give people an "out" by checking a box which tells the center to draw and discard their blood. That way people who fear they may be high-risk donors can get the social approval of donating without harming any patients.

Comment author: Alicorn 25 December 2010 07:09:59PM 4 points [-]

unless you've been pregnant a couple times - in that case, consider stopping

I've never been pregnant, but what is it about multiple pregnancies that renders the blood non-preferred?

Comment author: Eliezer_Yudkowsky 25 December 2010 07:18:25PM 3 points [-]

Obvious guess: Your blood then contains antibodies to the blood type of your babies.

Comment author: Marius 25 December 2010 07:25:27PM 2 points [-]

Essentially this. The A/B/O blood groups represent the most relevant antigens in human blood. There are a host of others (Rh, Duffy, Kell, etc.) which typically create only minor problems in a transfusion and which can be ignored in an emergency. But a person who has been exposed to allogeneic blood via multiple transfusions or pregnancies becomes more likely to develop antibodies to some of these antigens. The donor's antibodies or white cells can react to the person being transfused, causing lung damage.

Comment author: wedrifid 25 December 2010 08:48:28PM *  3 points [-]

There are a host of others (Rh, Duffy, Kell, etc.) which typically create only minor problems in a transfusion and which can be ignored in an emergency.

In the case of the Rhesus factor it should be noted that it is minor once and then only minor for males. Being thereafter unable to safely give birth to healthy Rh+ children is definitely not a minor consequence even if it is better than 'probably going to die today'. (Unless, I suppose, you happen to some Rh+ antiserum lying around but no Rh- blood, which will usually avoid the future difficulties.)

Comment author: Marius 25 December 2010 10:34:27PM 6 points [-]

I use "minor" differently than you do, to mean "unlikely to cause death". Obviously cross-matched blood is always preferable for a variety of reasons (including possible infertility, in the case of young females).

I would avoid RhoGam in the case of a patient who needs a RBC transfusion, incidentally. It would be unlikely to be safe or effective.

Comment author: shokwave 26 December 2010 09:50:13AM *  4 points [-]

I use "minor" differently than you do, to mean "unlikely to cause death".

I would like to express that my approval of this phrase extends beyond the capacity of upvoting and into the capacity of a comment expressing approval.

Comment author: wedrifid 26 December 2010 10:04:43AM *  1 point [-]

I use "minor" differently than you do, to mean "unlikely to cause death".

And having both your arms removed is "Just a flesh wound!".

Comment author: TobyBartels 26 December 2010 08:04:40AM *  0 points [-]

Oops, I see that this has already been asked.


we've set up a system that subtly encourages certain types of donors and discourages others

While we've got you here, can you explain why gay men cannot donate? This upsets a lot of gay people that I know.

I understand that it's easier to catch STDs (not just HIV/AIDS) from a man than from a woman. But the current U.S. rule (A man cannot donate if he's had sex with a man; a woman cannot donate if she's had sex with a man who's had sex with man.) is lopsided.

The even-handed rule that you cannot donate if you've had sex with a man would keep the supply safe without having to rely on people's being able to trust their partners. But it would keep most women from donating, so maybe it's not worth it. The even-handed rule that you cannot donate if you've had sex with man who's had sex with a man would still keep out most gay men, but it would probably help to heal the rift.

Comment author: Alicorn 26 December 2010 01:11:13PM 1 point [-]

The even-handed rule that you cannot donate if you've had sex with man who's had sex with a man would still keep out most gay men

If a man is gay and sexually active, he's almost certainly had sex with a man who's had sex with a man, even if the men he has had sex with has only had sex with him. I don't see how this phrasing of the rule would be an improvement.

Comment author: TobyBartels 28 December 2010 12:17:07AM *  0 points [-]

My phrasing was unclear; make it "if you've had sex with man who's previously had sex with a man (other than you)". There wouldn't be any point in forbidding me from donating (if I'm male) because the man that I've had sex with has had sex with me!

This change would include more people; it includes monogamous gay male couples who began their relationship as virgins (as well as some other people). Not many more, but it makes it clear that the blood collector is only willing to trust you and your partners, no further.

Frankly, the first even-handed rule (no sex with a man, period) makes more sense to me. Why should the blood collector trust that I know (if I'm a woman) whether all of the men that I've had sex with have had sex only with women? (No doubt many women are donating contrary to guidelines because they don't know this about their partners.) But because this would cut the potential donor pool in half, the blood collector is basically forced to trust me about my partners too.

In fact, the blood collectors trust women to know the sexual history of their partners, but not men. They are not asking everybody the same questions.

Comment author: TobyBartels 30 December 2010 07:36:05AM *  0 points [-]

Another possible solution, not even-handed, but more honest: Just don't ask women anything about the subject.

The idea that a person can be trusted to know about their partners' partners is preposterous; no other question (in the U.S.) asks the donor about other people's behaviour, and for good reason. Instead of half-assedly trying to be even-handed about it, just admit what they're doing: ruling out men who've had sex with men, because many of their partners will have had sex with other men, and so on back (in many cases) a long way; but accepting women who've had sex with men, because most of their partners won't have had sex with men, stopping the transmission-from-men sequence.

I'm confident that they already accept blood from most women who've had sex with men who've had sex with men (because the women don't know this about their partners), and they are surely aware of this (if I am correct) fact. So why are they asking questions of people who don't actually know the answers?

Gay people will still be upset that they can't donate, but I at least would be more willing to trust that the blood collectors are actually making an honest decision.

Comment author: TheOtherDave 30 December 2010 05:35:54PM 0 points [-]

Mostly, my faith in the quality of the blood supply derives from what testing they're doing to the blood, not from what unenforceable policies they're suggesting to the donors.

I'd actually be surprised if the latter significantly affected the quality of the blood.

Mostly, I think the problem they are a solution for is maintaining public confidence in the blood supply. Which I acknowledge is an important problem. And it may well be that being perceived as excluding gay men and their partners is a better solution to that problem than anything else they might do; I don't know.

That said, if I'm wrong and these policies really do solve a problem related to the blood supply, yet another possible solution is: don't allow people who have had unprotected sex to donate.

Or, if that's too big a chunk of your potential donor base, make it people who have had unprotected sex outside of a monogamous relationship.

Comment author: shokwave 26 December 2010 01:54:35PM *  0 points [-]

The original rule bars 'a man who has had sex with a man' - X - and then any women who've had sex with X. It's a logical phrasing but unfortunately X maps exactly onto "gay man", so it feels like gay men are being specifically targeted. The rephrasing mollifies that sense of targeting without, as far as I can tell, changing the included or excluded people.

The original phrase is even-handed, however. If you overspecified an even-handed rule and said "1) You cannot donate if you're a man who has had sex with a man who has had sex with a man, and 2) you cannot donate if you're a woman who has had sex with a man who has had sex with a man" - ie, prevent "man who has had sex with a man" from coming into sexual contact with any donor - you could reduce 1) down to "man who has had sex with a man" (it logically implies three, four, and so on iterations). This, therefore, reduces down to the actual rule they have in place.