A more efficient plow can increase agricultural yields and a machine that can automatically core apples will remove the need for people to core the apples -- is there an equivalent for medical diagnostics?

Better tests and more access to diagnostic tools helps medical productivity to some degree, although unnecessary testing pushes the other way. And sometimes better diagnostics leads to more interventions which may mean more labor (and sometimes better outcomes too)

When it works, imaging (x-ray, CT, MRI, etc.) is ridiculously effective.

There's also stuff like figuring out that bacterial infections are a big contributing factor in ulcers. Once doctors believed it was true, interventions got a lot more effective.