Other tests should be solved too (fecal/urine/blood). Perhaps we need more R&D in here to accelerate progress.

We already have patients trying to track their own health over longer time which is great. We then just have to make AI good enough to spot warning signs (without patients asking). Or parhaps we need to make those tests easy and cheap and regular.

> Perhaps we need more R&D in here to accelerate progress.

In general yes, just that "more" is monstrously massive to the point of it being closer to science fiction than reality, IMO.

To reiterate, various assays fluctuate rather wildly over the course of various body cycles. The reason(-s) your doctor should remind to get a blood drawn in the morning after a period of fasting is that the sample is taken at a somewhat steady state and the result is comparable to reference values without too much of a margin.

Anyone with a requirement to manage blood glucose levels will tell you that CGMs are vastly superior to finger pricks first and foremost due to the sample rate available and comfort reasons secondarily. With a finger prick test the patient is only somewhat aware where in the curve they are, which makes the test only a rough estimate due to this temporal error margin. A lot of people do not zero in their readings with finger pricks as they are mostly interested in the deltas.

Suppose you manage to make urine sampling relatively accurate and super cheap (e.g. tens of eurodollars per analyzer or cents per test strip) so you can have poorly-supervised, long-term studies with huge cohorts. However, unless you somehow control for sample collection conditions, all this baseline variability suddenly infects your whole dataset and effectively raises noise floor. It's not unreasonable to expect that whatever was found to be a useful signal under controlled conditions to fall below noise floor under uncontrolled conditions.

That's basically THE problem with the hypothetical test-it-all machine. Again, maybe in some cases that could be extremely useful, but in a lot of cases that would be counter productive. However, what CGMs hint us at is that various kinds of Continuous X Monitors could provide insights into body reactions to things, which is, currently, effectively not a signal in general medicine. Once the test-it-all machine is reframed as an array of continuous monitors and the useful signal is reframed from long-term drifts to short-term deltas it may unlock some additional diagnostic pathways.