This could sort-of work. In The Netherlands, healthcare is billed according to a"diagnosis-threatment combination" (DBC, diagnose-behandel combinatie in Dutch)

This could sort-of work. In The Netherlands, healthcare is billed according to a"diagnosis-threatment combination" (DBC, diagnose-behandel combinatie in Dutch), which is a government-mandated set of billing codes. Each code covers the whole diagnosis/threatment pipeline, for example "uncomplicated total knee replacement" which covers imaging, surgery, and a few days of revalidation until you leave the hospital. As these codes are standardized, it is relatively easy to know in advance what it's going to cost the insurance company. The codes are sort of overlapping, for example a breast MRI has it's own code (usually 270eu, but with outliers both ways), but there's also a code for the combination of a mammography, breast MRI + lumpectomy. Hospitals are nowadays obliged to publish these pricelists, even though insurance is mandatory etc., after some court cases involving uninsured people not knowing costs in advanced. Just having these lists could work wonders in terms of transparency.