When is the best time to use a pregnancy test for accurate testing? Pregnancy is a topic that concerns every woman, and pregnancy tests are one of the most commonly used methods to detect pregnancy. However, you need to use the pregnancy test at the correct time, otherwise the results may be inaccurate. Generally speaking, how many weeks into pregnancy should a pregnancy test be used for an accurate test? First of all, what needs to be clarified is how long does it take to detect pregnancy with a pregnancy test stick?