What causes false positive pregnancy tests
False positive pregnancy tests are incredible rare. If you have a positive pregnancy test then you need to assume it is correct and make an appointment with a doctor. Positive home pregnancy tests are so accurate that most doctors accept that as a confirmation of pregnancy.
If you have a positive pregnancy test and then take another test and it is negative then you can assume the negative test is incorrect. Fasle negative pregnancy tests are common.
False positive pregnancy tests are more common with blue dye pregnancy tests though. I suggest only using pink dye pregnancy tests to reduce the risk of getting a false positive. Sometimes a second line will show on a blue dye pregnancy test but it isn't a real line, it is an indent and looks very close to a real positive.
Always make sure that you are follow the directions on a pregnancy test. You can only look at the result in the amount of time specified by the test. If a positive result shows up after the time frame in the instructions then you can not count it as a positive.
And then I learned what an evaporation line was. THANKS test for scaring me to death.