[mreiner]

From what I understood about how the system works in most European countries:

A test has a specific sensitivity and a rate of false positives. So for screening (CT in this case) you would want a high sensitivity and low cost, while the false positives would not be your priority. The positives should go through a confirming test (biopsy in this case) with a high specificity. Here cost and sensitivity are usually secondary.

Now insurers look at the screening tests rate of false positives. If they deem it too high, they don't want doctors to do those tests on a population with a low probability of having the condition you are screening for (low base rate). If the patient belongs to a subgroup shown to have a high enough base rate of a condition, then it makes sense to do the screening.

Then you have different patients, some want to get one MRI each year, some only want to run diagnostic after they experience symptoms. I believe most doctors respect that individual risk tolerance within the given framework.

Now the thresholds obviously should be revised regularly as cost, test properties and even base rates of diseases change, but I don't see a systemic defect here, my blind spot?