How accurate are the preterm labor tests? Cant remember the name but its to see if you will deliver in the next 7-14 days..

Went to the traige for not feeling good. Doctor was concerned about babys heart rate at first cause it was going up or down it was staying one number. Then we got baby to move and it was to high. They did the preterm test and it came back positive.. im just wondering how accurate can the test be ? I do housekeeping so i dont want to bring on labor any way quicker.. ive had shot to stop contractions on my uterus and the steriods for the babys lungs just in case..