If the pregnancy test is blank and there is no bar, if the control line shows normally but the test line is blank, it may be that there is no pregnancy or early pregnancy has not been shown yet, or it may be related to the operation error. If both the control line and the test line are blank, it may be a problem with the quality of the pregnancy test stick and a new stick can be purchased to test again. When the control line is positive and the test line is blank, it may be because the woman is not pregnant and there is no human chorionic gonadotropin in the urine, so the pregnancy test will not show a positive reaction; it may also be because the HCG content in the urine in early pregnancy is too low or the waiting time is too short, so it is better to wait for 3 minutes and observe. If you are not sure, you can test again after 1 week, or you can go to the hospital to check the blood HCG to accurately determine if you are pregnant. If both the control line and the test line are blank, it is possible that the pregnancy test stick is out of date or damaged, or it is possible that not enough urine was collected, so you can buy another one and test again. When using a pregnancy test stick, it is recommended to choose early in the morning and use the morning urine for testing. It is necessary to ensure that the amount of liquid is sufficient to penetrate the small hole on the observation window, and it is better to wait for 3 minutes before observing the result, which is more accurate. Due to the nature of the test method, if you wait more than 5 minutes before observing, you will easily get a false positive and the test will be invalid no matter how many bars there are.