I am also 31 weeks today and VERY low!! My doctor didnt do any test...but did say that if I dont stay off my feet im gonna end up gonna into preterm labor. Its a lil scarey esp cause im such a clean freak (alil OCD) I have to clean EVERY day!!!
Good luck with everything and keep us informed!!!!!!
My daughter was also sitting very low and engaged at around your stage of the pregnancy. Because of another issue, I was induced 8 days before the due date. I didn't get a test done but I'm guessing they are testing to see your chances of preterm labour. Good luck!
I believe she will be just running a test to see if you might go into preterm labor. Its not 100% but they can do a test to see what the chances are that you would have your baby before term. Based on how low baby is they are probably just taking precautions. You want to keep that baby in as long as possible:~) Good luck!