Home pregnancy test. Packet and contents of a 'Boots own brand' home pregnancy test kit. The test works by detecting the hormone human chorionic gonadotropin (hCG) that is present in the urine of a pregnant woman. A dipper (lower right) with an absorbent end is placed in the urine stream, or dipped in a urine sample. Blue lines in windows on the side of the dipper display the results after three minutes. A reference line in the smaller window confirms that the test has worked. A blue line in the results window confirms the presence or absence of hCG. HCG is produced by the placenta, the organ that attaches an embryo to the wall of the uterus.