What is a pregnancy test strip? Pregnancy test paper is a special test paper that can quickly detect whether the human body is pregnant. It mainly relies on the pregnancy hormone (HCG) in the urine to detect pregnancy. In the early stages of pregnancy, after the egg is fertilized, the HCG level will rise rapidly. At this time, use a pregnancy test paper to test the urine. If the test is positive, it means that the woman is pregnant. What are the two lines on the pregnancy test paper?