A false-positive test can be caused by a long series of factors, such as some cancers, cysts on the ovaries, also some types of hormonal drugs or the state in which the woman is immediately after childbirth or abortion. On the contrary, a false negative test can come out to women using diuretics, which are drugs that promote urine excretion, or antihistamines that block the effect of histamine. Too thin urine can also be the cause of a false negative result.\r