If a doctor buys it for $80 he will then have to sell it for...

If a doctor buys it for $80 he will then have to sell it for $120 to $200 which then makes the test more expensive and therefore less desirable. Doctors will more likely purchase boxes of 10 for $400 which cuts the profitability. Probably that will still happen and the retail price will probably be the same. Selling direct keeps more profit with the company but possibly upsets doctors. But if the test becomes the gold standard screening test then the company has the sword in both hands and doctors will have to use it.
And it is a screening test, and it will ultimately be the doctors decision, based on other tests and procedures (ultrasound, MRI, Xrays, hormone and enzyme asays, exploratory surgery), to surgically remove the ovary and little blame can be placed onto the test for false negatives and false positives the accuracy of which are researched and known.