When they warn of rare disorders, these prenatal tests are usually wrong
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Re: When they warn of rare disorders, these prenatal tests are usually wrong
#2Behold, the curse of Reverend Bayes:
Re: When they warn of rare disorders, these prenatal tests are usually wrong
#3I recall a period in the early 2000s when unindicated whole-body CAT-scans were being advertised on television.
That got knocked down pretty quickly but wow a lot of folks picked up a big chunk of their lifetime radiation allowance because of that.
These tests seem to operate under a similar model, disregard the risks of unnecessary testing in return for information of limited utility that may cause material harm.
Re: When they warn of rare disorders, these prenatal tests are usually wrong
#4This seems to miss the point entirely. Even for their worst example the odds of the fetus having it go from 0.005% to 7%. That's valuable information even if it's not perfect or somewhat hard to understand.
Re: When they warn of rare disorders, these prenatal tests are usually wrong
#5Interesting.
We have been undergoing IVF with my wife since 2019. (Covid made a huge mess of those plans...) One of our embryos tested as a possible positive (but only slightly) for aneuploidy of one chromosome.
The doctor, a veteran of IVF, looked at the results and said "my experience is that this is either a very small mosaic error, which tends to be utterly invisible in real life, or a computer artifact. I have never seen embryos with those borderline results develop any serious problems later. Things would be different if the aneuploidy signals were clear, but definitely do not discard this embryo".
Re: When they warn of rare disorders, these prenatal tests are usually wrong
#6Before my daughter was born I sometimes felt like it was the doctors job to scare us with every worse case scenario possible. It was quite stressful and upsetting.
Re: When they warn of rare disorders, these prenatal tests are usually wrong
#7Re: When they warn of rare disorders, these prenatal tests are usually wrong
#8This seems to miss the point entirely. Even for their worst example the odds of the fetus having it go from 0.005% to 7%. That's valuable information even if it's not perfect or somewhat hard to understand.
This would be valuable for running some extra tests (possibly more expensive, but more accurate), but not for, say, decision to abort the kid, which is what usually "hangs in the air" after such a test result.
Re: When they warn of rare disorders, these prenatal tests are usually wrong
#9This article is a confused mess. It's something of a Gish gallop in conflating all the different issues they could come up with, while leaving out all the necessary vocabulary (C-f "Bayes" "posterior" "decision theory" [Phrase not found]) making it almost impossible to consider each issue in adequate detail.
It mixes up poor communication (reporting false-positive/negative rates as if posterior probabilities, & exaggerated confidence thereof), arbitrary-seeming decision thresholds (but their hyperventilating over '85% wrong' notwithstanding, many are probably too conservative, if anything, given how devastating many of these problems are, there should be more false positives to trigger additional testing, not less), costs of testing (sure why not but little is presented), tests which they claim just bad and uninformative (developed based on far too little _n_, certainly possible), implicit calls for the FDA to Do Something and ban the tests (not an iota of cost-benefit considered nor any self-reflection about whether we want the FDA involved in anything at all these days)... Sometimes in the same paragraph.
Plenty of valid stuff could be written about each issue, but they'd have to be at least 4 different articles of equivalent length to shed more light than heat.
Re: When they warn of rare disorders, these prenatal tests are usually wrong
#10> “The chance of breast cancer is so low, so why are you doing it? I think it’s purely a marketing thing.”
This mindset is ingrained in every doctor I speak to, but I think it's just so wrong.
Take DiGeorge syndrome. You have a 1/4000 chance of having it, and the test carries an 81% chance of a false positive. The above doctor calls this "marketing"? Foolishness. That's an incredibly useful test. The downside is small, and the upside is asymmetrically large.
We need far, far better screening for all sorts of things. Adult cancer and heart screens once a year, prenatal screening, and on. We do a good job with breast and prostate screens, but for rarer conditions our current approach of waiting for the disease to be symptomatic makes no sense. Part of that will be driving the cost down. There is so much market need for a legitimate version of Theranos and I'm glad there are some companies working on these things.