If you find three bars after using a pregnancy test, it means that there is a quality problem with the test or the test is no longer valid, and you need to change the test again. Women in normal circumstances after the use of pregnancy tests will appear 1-2 bars, if pregnant through the urine test in 3-5 minutes will show two bars, the principle of pregnancy test is through the detection of women’s urine, the concentration of chorionic gonadotropin contained to determine whether the pregnancy, women in the body of the chorionic gonadotropin in the pregnancy was every other day doubled the growth of the pregnancy test can not be completely sure whether the pregnancy. Can be clear through the blood test, women using pregnancy tests before the recommended to stay in the morning in the middle of the urine, this time the test is more accurate, and check the results immediately after 3-5 minutes, the results of too much time is prone to error.