> "it sounds like ctDNA may not be accurate for her anyway since Ca19-9 has consistently been low?"

That sounds logical and seems to fit my (and Amy's mom's) pattern, but I have no data or qualifications to generalize that to other patients or cases.

> "they haven’t adopted it for use yet due to unclear benefit"

I've had it rejected by insurance as "medically unnecessary" several times, but my hospital has always found some way to get it reimbursed.