These diagnostic tools detect the presence of human chorionic gonadotropin (hCG) in urine, an indicator of pregnancy. The visual distinction arises from the type of dye used in the test strip: either a pink-dyed conjugate or a blue-dyed conjugate binds to hCG, resulting in a colored line that signifies a positive result. For instance, a test utilizing a pink dye will display a pink line if hCG is present above a certain threshold.
Their significance lies in providing early and accessible confirmation of pregnancy. Historically, women relied on less reliable methods, but these tests offer a convenient and relatively accurate means of determining pregnancy status within days of a missed menstrual period. This early detection allows for timely access to prenatal care and informed decision-making regarding reproductive health.