Pregnancy test kits require you to test a sample of your urine. The absorbent wand reacts if a hormone called hCG (human chorionic gonadotrophin), which is produced by the embro, is present in your urine. As a backup, many kits include a second test.
How to use a test kit Not all kits look like the one shown here, but they work in basically the same way. Remove the test wand from the cap or cartridge. Hold the absorbent sampler in your urine stream for a few seconds. Replace the wand into the cartridge. Wait as directed. If you are pregnant, both windows will show a color.