There’s a lot of umbrella diagnoses that would benefit from more specific diagnostics first. What we call Alzheimer’s is probably actually caused by number of different causes depending on the person. This is true of a lot of things in medicine that get grouped together. That’s why testing a drug in mouse models with all the same characteristics sometimes works but fails to translate into humans who have more variety amongst each other.

The same is true of many diagnoses like pneumonia, cancer, alopecia, essential tremor: there’s multiple different groups that would benefit from different things, and if we had better ways to identify the groups, we’d give them what works for them instead of wasting their time with the wrong treatment. As an example, antibiotics won’t work for viral pneumonia and in addition to wasting the patient’s time, actually harm your microbiome. If you had a perfect way to know which is which, you’d always get the right treatment.

Precision medicine takes this even further.