Is the weak positive on the pregnancy test paper true? Pregnancy test strips are a tool commonly used to detect pregnancy. However, sometimes there are weak positive results, which makes people worry about whether they are really pregnant. This article will discuss the authenticity of the weak positive of early pregnancy test paper and how to judge whether it is a false pregnancy from the following four aspects. 1. How does the pregnancy test paper work? The pregnancy test paper measures the concentration of chorionic gonadotropin (hCG) in the urine to determine whether you are pregnant.