I'm really sorry to hear that. I think we've all been in that situation a number of times, waiting on tests for loved ones.
It could be a number of things, but ultimately, it is what it is, and worrying won't change it. Is your mom worried? If so, see what you can do to help her deal with the waiting. If not, try to follow her lead.
Believe me, I get it. I panic every time my mom has her physical. Good luck and try to stay distracted. It helps me a lot.