[hire_charts]

I never really understand this argument. People make it about increasing the frequency of blood tests too. Or MRIs. Doctors are afraid of finding "incidentalomas", but why can't we instead just change the way we think about the data?

More data does not inherently mean more scares. If anything, it means that a false positive here and there will be less likely to upend someone's life, because doctors will be more focused on identifying trends, and will be more able to simply ignore outliers.

[giantg2]

In the case of certain tests, like MRIs, there can be scheduling or cost constraints. This is one if the primary reasons that they still use CT machines for suspected stroke patients - the machines are cheaper and thus more available on short notice, eventhough MRIs will provide better soft tissue and vascular images.

This leads into the second part. Nothing happens in medicine without some risk. Sometimes the best way to "do no harm" is not to do anything. For examples, the repeated use of CT scans on a patient will increase their risk of cancer. It was estimated/theorized that the overuse of CTs may be leading to 50k excess or early deaths in the US each year. Obviously MRIs don't have the ionizing radiation, but they are more scarce and generally more difficult to schedule, so priority tends to go to patients with specific types of issues, generally ones confirmed by other tests that need higher resolution imaging (like a brain tumor found on a CT).

I do agree that simpler and cheaper tests can be thought of and viewed differently. Even today, most of the time any positive test will be confirmed with at least a retest. Sometimes the sample will be tested 3 times or even shipped to another lab(s) for thorough confirmation (many negative tests should be retested similarly too). If the doctor or lab that you're currently using uses just a single result, I would consider switching.

[perl4ever]

>a false positive here and there

Is that the right characterization? If everyone got a test every year, then there would be 3% false positives, per the article.

Brain cancer cases are around 6-7 per 100,000 per year.

So that means simply screening everyone would produce around 99.8% false positives, wouldn't it?

Or, looking at it another way, there would be 400 - 500 false positives for every real one.

"More data" implies that you use it for something. If there is some kind of intervention, and it almost always is not needed, then it has to be that much safer, in order to not make people worse off in aggregate.

This has long been a controversy with mammograms, I think.

[hire_charts]

If the tests are cheap and can be performed as frequently as necessary, I could imagine a system where a test isn't considered positive until a statistically significant number of them have come back positive. If there is an abundance of data, there is no longer a need to extrapolate from a single data point.

I had a blood test once where my electrolytes were somewhat out of whack. I wasn't called in for an expensive kidney scan or consultation with a urologist. I was called in for another blood test. The second test came back fine. I was likely dehydrated the day of the first test.

The availability of cheaper, more frequent testing means that the response to a single positive signal does not have to be as extreme. Thankfully my doctors office offers walk-in blood testing or my experience could've been a much more anxiety-inducing hassle.

[perl4ever]

Are false positives always uncorrelated with each other?

I would think it would depend on the nature of what causes them.

[giantg2]

True. I've heard of some tests coming back false positive or false negative from specific labs based on the way they did the test. I hear that Lyme disease is a particularly tricky one to get right (or has been in the past).

I've also been told that if you need tests done, it's best to get them dome during the week. Sometimes in some places the weekend team is the "B team" or techs on Friday afternoon just want to get done and make more mistakes. This seems to be similar to the research done about patient outcomes being affected by their surgeon's birthdays being on the procedure date, etc.

[dzhiurgis]

Well technically you should've had 2 follow up tests. Or 2-3 initial tests for actual data point.

I agree we need to improve this, yet we are in such an early age of medicine is basically a joke. There are nowhere near enough doctors to even scroll thru your tests, let alone to analyse them. The focus still is mostly on curing the most obvious symptomatic cases.

Also tests require tons of samples. IIRC there's over 2000 different blood tests. Unsure of minimum blood volume needed, but even at 1 ml that's already 30% of your total blood volume! I guess pee is easier lol.