I can't see their detection mechanism being a secret - everything about the hormones and placenta and such are pretty much out there in medical science. The lab process might be, though. Could easily be that they have come up with a more effective way of measuring whatever it is than anyone has had.
I'm curious, though, if that sort of thing needs FDA approval, since it's not actually going into a person during the test (I assume). I mean it's got a near 50-50 chance of being right no matter what...