Recommended labs--is there a list somewhere?

Yes, unlike some of the other vitamins, Vit K is absorbed many spots (but including the bypassed portion). I suspect that the change in diet is more responsible than the bypass itself since even those who actually eat green leafy vegetables, bananas, etc. that are high in Vit K don't eat nearly as much of them.  Who has room for very much kale (even if they wanted it)?!?

Good point about the testing frequency, though. I don't know how many surgeons test for it.  Mine did, but I don't know how many do.  Mine was low for a while but the hematologist had a fit when he found out we were supplementing it (because I also take blood thinner) so we just leave mine low.

Yeah, I'll go with "low" on yours, LOL.

Very helpful explanation about why different docs test at different intervals.  I appreciated this.