A pregnancy test is a medical tool used to determine if a person is pregnant. It works by detecting the presence of the hormone human chorionic gonadotropin (hCG) in urine or blood. This hormone is produced shortly after a fertilized egg attaches to the uterus. There are two main types of pregnancy tests: urine tests, which can be done at home, and blood tests, which are performed in a medical setting. Home tests are typically easy to use and provide results within a few minutes, while blood tests can offer more accurate results and detect pregnancy earlier.