I'm not sure I quite understand your question, but I'm guessing you are asking if a pregnancy test can show up negative when you are in fact pregnant. Is this what you are wondering? If that's the question, yes, it's possible for a test to be wrong. I hear there are less false positives and more false negatives. Some medicines can cause a false positive result in a pregnancy test. It can show negative when you are pregnant maybe if it's too early for the particular test. If you think you are pregnant, I'd try a few different brands of tests or see a doctor about it. First Response has a test that is supposed to be very accurate when taken the time of your missed period.