The state mandated tests in California are far worse. At least with NIPT tests, if you get a negative, it's fairly certainly a negative. The state tests have all kinds of unnecessary false positives, and if you don't have the NIPT to negate them, you are in for a lot of worry.
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
#92My wife and I went through this a couple of years ago, with a 10 week NIPT calling a rare trisomy (chr 9), which is always fatal within a few weeks of birth. It was absolute hell. The key problem here is the waiting and uncertainty. You have the NIPT at 10w, but you can’t have the amniocentesis until several weeks later. When that came back fine, there were questions about whether it was a “mosaic” meaning only a sma…
Did you repeat NIPT test?
Re: When they warn of rare disorders, these prenatal tests are usually wrong
#93Earlier quoted context omitted.
Having gone through two twin pregnancies (where the odds of these tests being correct are especially low) we declined all of them. Anecdotally, I know of several parents who had a positive test for genetic disorder, went ahead with the pregnancy anyway and children were perfectly healthy. Until these tests are close to 100% reliable I don’t see the point.
"it worked out fine for me" is not particularly reassuring when the alternative is a lifetime of medical bills and possibly a permanent dependent.
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Re: When they warn of rare disorders, these prenatal tests are usually wrong
#94Earlier quoted context omitted.
Is it better to terminate 85 pregnancies which do not have a serious defect in order to catch 15 which do? At what point is it not better to terminate 100% of pregnancies?
> Is it better to terminate 85 pregnancies which do not have a serious defect in order to catch 15 which do? Yes, it’s absolutely better to do that. Of course, the actual ratio is much better than that because we do follow-up tests after the screen.
Your first question and answer is against medical ethics. If you’re a physician you know that terminating pregnancies based on a non-specific but sensitive screening test is inappropriate (do no harm).
However, you are correct in your second statement - there are much more specific follow up tests which improve diagnostic accuracy.
Medical utilitarianism should never be so cruel and gruesome as to eliminate 85 healthy and wanted pregnancies in order to find and eliminate 15 genetic aberrations.
Re: When they warn of rare disorders, these prenatal tests are usually wrong
#95We were told our son had a high chance of being born with down syndrome. It was quite stressful to hear this as we weren't going to do anything about it regardless (he was born with no issues whatsoever and is now a thriving young adult).
Re: When they warn of rare disorders, these prenatal tests are usually wrong
#96Earlier quoted context omitted.
Having gone through two twin pregnancies (where the odds of these tests being correct are especially low) we declined all of them. Anecdotally, I know of several parents who had a positive test for genetic disorder, went ahead with the pregnancy anyway and children were perfectly healthy. Until these tests are close to 100% reliable I don’t see the point.
"it worked out fine for me" is not particularly reassuring when the alternative is a lifetime of medical bills and possibly a permanent dependent.
The alternative is loving a human being and playing the cards you’re dealt
Re: When they warn of rare disorders, these prenatal tests are usually wrong
#97IMHO, some of those criticizing the article for failing to understand statistics are missing the point. The point is that people who get a "positive" result on these tests are often put through terrifying levels of anxiety when there is no actual problem; this anxiety is often exacerbated because they aren't informed of the false positive rate. This clearly has a harmful emotional effect on people, and explaining the…
If you get a positive for a horrid cancer with a 90 percent false positives you should be afraid. Its lunacy for tests to be regulated beyond requiring rough false positive false negative rates, and if anything smacks of "I dont understand statistics and therefore have to protect my children from understanding statistics." The article is most likely written by some anti abortion idiot.
> if you get a positive for a horrid cancer with a 90 percent false positives you should be afraid.
No you should not panic, anymore than you should celebrate and buy a yatch if you think you have 10% chance of winning a lottery.
The doctor should phrase it as "the test indicates you have a 10% possibility of cancer. The majority of people who test positive do not have cancer. Further testing is required to confirm or rule it out."
Going with the expected value of 10% of a horrid thing is still bad, or 10% of $100m is still $10m, is not applicable to a single non repeated event.
Re: When they warn of rare disorders, these prenatal tests are usually wrong
#98Earlier quoted context omitted.
I am sorry for your horrible situation. I don’t really understand what your implication is. Are you wishing you had not done the genetic tests? Suggesting you should have aborted the 20-week fetus based on unusual skull appearance? Suggesting that the meningitis was a result of some malpractice? Mad at medical professionals who are now “dropping hints” without saying something more substantive? The problem with these…
I've always wondered-- is the error between tests correlated? Why does it not suffice to gather all the positive outcomes and test them again, then again and again until you have sufficient power depending on the rarity of the disease in the population? I know that for covid tests for example the test outcome errors aren't independent, which is why even taking several tests you can't be confident you're negative even…
I think of it like this:
Unlike a false negative where there isnt enough to trigger the test, false positive implies that something triggered a positive.
You have something, just not what the test thinks you have. For example, men with testicular cancer, apparently, show up as pregnant in pregnancy tests. Clearly thats a false positive for pregnancy.
Re: When they warn of rare disorders, these prenatal tests are usually wrong
#99IMHO, some of those criticizing the article for failing to understand statistics are missing the point. The point is that people who get a "positive" result on these tests are often put through terrifying levels of anxiety when there is no actual problem; this anxiety is often exacerbated because they aren't informed of the false positive rate. This clearly has a harmful emotional effect on people, and explaining the…
I've worked clinically and taught this in professional training programs. It's a classical clinical decision making problem.
The solution is fairly straightforward I think: require the test companies to report the posterior probability of the illness given the test result. Probably with some kind of uncertainty interval.
Re: When they warn of rare disorders, these prenatal tests are usually wrong
#100Earlier quoted context omitted.
"it worked out fine for me" is not particularly reassuring when the alternative is a lifetime of medical bills and possibly a permanent dependent.
The alternative is loving a human being and playing the cards you’re dealt
The alternative is to take the same energy you'd spend on that one unlucky human being and spend it raising 3 healthy children who will go on to live full lives.
Parenting is an enormous time investment and families that take on the burden of raising disabled children almost universally reduce their family size. This is not a decision without cost, to those who lose their chance at life.