evidence: Home pregnancy test kits detect pregnancy by picking up on the presence of a hormone called human chorionic gonadotropin (hCG) in urine. Pregnancy can also be detected at the clinic using a blood test for hCG. The claim that pregnancy can be confirmed by the way salt reacts to urine appears to borrow elements from how home pregnancy test kits work. However, there’s no known mechanism by which salt reacts to the presence of hCG, and thus it isn’t a reliable method for confirming pregnancy.