If you're gay keep your heart to yourself?

[shade_42]

CBC just issued this article about sexually-active gays being prevented from becoming organ donors. Or are they? Sounds like there are a few groups in the organ chain of command that disagree

Comments

[finneco]

People disagree about the statistics and the studies, but from what I have heard, the distinction isn't warranted, or at least is badly phrased.

For the blood supply, there are two issues: avoiding infected blood and detecting infected blood. All collected blood is tested in batches, but many diseases are not detectable, given current tests, for the first few weeks or months (maybe sometimes more) of infection. This means that it is important to avoid collecting blood from individuals who are at risk of having recent acquired an infection. Besides that, it really sucks to have batches of blood test positive for something and need to throw out 50 or so donations, so there is also reason to avoid collecting blood from individuals who are at high risk of unwittingly carrying an infection.

That is the part everyone agrees on. It's the filtering process of high risk individuals of either type that is more of a problem. I can't cite the studies, but I've been told that even in North America, straight women of some twenty something range have the highest rate HIV aquisition, and having spent some time debating the issue of the filtering process, I am inclined to believe that questions about safe sex practices would be much more accurate means of distinction for STI's. But don't asking me to draft such alternate wordings, at least not right now.

I have also heard that the reasons for the donor filtering process including the descriminatory clauses against men who have had sex with men are political rather than scientific, in part to keep the blood supply regulations in line to allow sharing across borders (provincial and national), and also to keep/rebuild the trust of citizens after the tainted blood scandals and tragedies that came out in the nineties.

How does all that translate into organ donation? Well, the infection rate issues are similar, but the screening process must use information other people can be expected to know, but from the sounds of it, they are still asking the wrong homophobic questions, particularly given that it seems some testing of the tissues is done anyway.

Finn

[shade_42]

All good points, one question it raises for me is that if blood takes several weeks to check for various infections, would organs be take just as long?

Assuming they did, and considering we don't keep people on life support when there is someone in the next room who needs a new kidney right now, do these questions become more important? They're also less trustworthy as you are asking a 3rd party...

It seems to me that this is very similar to the blood case, but with greater immediacy (in the cases involved) and potentially more prejudice.

I was unaware that there are provincial difference in whose blood or organs can be excepted.

Finally, I don't see why the fastest group for acquiring HIV should matter here, only the highest at present. I worry more about the 40 of 1000 carriers of a certain group that has gone down from 50 than the 4 of 1000 for another group that has gone up from 2 (numbers made up for argument, not representative). Acquisition rates are very important to watch for controlling the spread of a disease, but for a situation like this I think the only number that matters is how likely someone of a certain group is of having the infection at the time of donation.

[finneco]

in terms of growth and measurement, since all statistics will be old, the measurement of the rates of growth should not be ignored. If a steady fast trend up was recorded over a period of time in one group, and a down-trend in another group, you have to consider how old your statistics are. If your static statistics are stale, the trend may be more relevant, no?

Oh, and didn't you know, 69% of statistics are made up on the spot.

[shade_42]

Your argument suggests that the trend of infection shouldn't be neglected, and I grant you that, but it doesn't match your conclusion that the trend will be more relevant than the total if your data is older. Remember my total number and my rate of growth number will be equally old, therefore equally untrustworthy.

Your certainly correct that if I know last year's total and rate of growth I can estimate this year's total, but the moment I suggest my data is too old, all of it is suspect.

Stats don't give you exactly right answers, but with care they can give you educated guesses. Sometimes that is all we need, often that is all we've got.

to clarify

[finneco]

The testing takes minutes to days, depending on the disease, but can give falsely negative results if the source was recently infected, and it's the size of that black window that is weeks to months long.

If they are testing, and depending on what they have time to test for, they can consider individuals with risk of unknown infection, just not recent acquirers. That is probably some of the reason for the boundary of MSM (Men who have had Sex with Men) in the last FIVE YEARS. I have heard more people quote one year as enough, but again we are looking for information that a family member might have, so the larger time scale means something.

Diseases do have a pretty good chance of showing themselves given enough time, so people often find out that they caught something the hard way, and would be screened with infection filters, not risk fo infection filters.

The aquisition rate thing is important in how it relates to the stereotype of high risk individuals. MSMers used to be the most high risk for aquisition, but now?

[shade_42]

Well that answer my questions about blood, and I presume that similar tests for organs take the same amount of time or less (after all they have the blood-filled body right there, they can just test that).

As for the rate of acquisition, I edited the original blog entry with a link to results someone found online for Canada.

[finneco]

Just to clarify, because it seems silly, but why would they batch N samples entirely, strictly for the purpose of testing. Wouldn't it make sense to mix a small portion (a sample) from each donation into a test batch, then test that. If the mix-sample-batch tests positive, you can explicitly test each associated sample.

Pick batch sizes and levels of heirarchy (batches of batches) based on statistical occurrence of positive tests, possibly per region, and the big O of the testing problem gets shrunk?

Of course, practicality/simplicity and the incredibly rapid influx of blood (I'm toungue in cheek for the latter) may make it more expedient to batch it all at once and toss it if it tests positive.

[shade_42]

I don't actually know the answer to your question, but I suspect your testing locations are centralized and transport in larger containers is simpler/cheaper/has a lower failure rate of container parts.

As such I would hope that they have optimized the batching similarly to what you described, transport the blood as short a distance as possible to be distributed according to need, then just send samples of each batch to the testing facility. Questionable test results then get e-mailed back to have batches destroyed locally.

Saves on freezer trucks and traffic congestion. Now of course the optimization in practice versus the real world scenario opens other lines of argument. Optimization outside of a computer program likely dies to diminishing returns quite quickly.

Shade

[ramou]

Optimization outside of a computer program likely dies to diminishing returns quite quickly.

I can definitely cede that. Suxxors to the real world.