Sometimes they get sick. No reason...just have an upset tummy. I have had three pups this week with diarrhea and vomiting. I took the first one to the vet and they found nothing except an elevated lipase which often happens for no real reason. You cannot always assume something awful is going on. Metronidazole cleared it. Then number two..and today number three. Guess they are sharing their little virus.
If she does not improve I would pursue other tests, but for now I would see if her tummy settles.
It certainly will not hurt to have BATs drawn .. I would wait until she is feeling better.