[timr]

Yeah, I get it. I read the book. I think his argument is wrong.

The point I am making is that for the “worried well” (aka “longevity enthusiasts”) you aren’t going to do anything differently based on the result. It's largely a waste of money for the sake of people who want to feel like they're Doing Something (tm).

If you really think about it, you're talking about the extremely marginal case where a) the patient had no prior symptom of an illness; b) the calcium scan is so bad that you'd put the person on a medication to manage a hypothetical future problem; and c) you weren't going to do it anyway based on other tests.

The three things together are vanishingly unlikely. The better argument, mayyyyybe, is that maybe the test is one of those things that motivates a certain type of person (again, the "longevity enthusiast") to do something they otherwise wouldn't do, but that kind of person seems like...the kind of person who wants to do things. So what is the goal?

See also: Vo2max, DEXA scans, and most of the other tests mentioned in the book. Great for nerding out on metrics, but...you aren't going to do anything you weren't already doing if you're the type of person to be getting the test in the first place.

[derbOac]

I'm not sure I disagree with your general argument but it's worth noting that aerobic sport forums are replete with examples of people who were considered extremely fit, right up until the moment they were in an ambulance due to an undetected issue that could have been anticipated with a scan.

Testing in general gets out of control but we as a medical community also have a problem I think of not identifying certain problems until it's too late. Some preventative testing could be done more, some less.

[timr]

> aerobic sport forums are replete with examples of people who were considered extremely fit, right up until the moment they were in an ambulance due to an undetected issue that could have been anticipated with a scan.

The primary lesson from this is to ignore stories you read in aerobic sport forums.

This kind of (usually apocryphal) tale is an example of the turtles, rabbits and birds allegory [1]. Testing is like a fence around a farmer's field -- it may catch rabbits, but it's useless for turtles (who will be caught, but move too slowly to matter) and birds (since you can't catch them with a fence). The "super fit person who randomly drops dead" is the very definition of a "bird" -- even if you assume the test is sensitive enough to catch the rare thing before it happens (usually not), you have the dual problems of timing (i.e. are you going to test daily?) and false positives for whatever rate of testing you do choose.

In real life, almost nobody has an illness that moves so quickly that it requires special screening, but so slowly that it can be stopped, or at least, that has a positive risk/reward ratio for the testing required to detect it. It's the fundamental problem of medical testing, and even most of the recommended tests have a very small expected benefit.

[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC4865494/