Two bars on a pregnancy test usually indicate pregnancy, but there can be errors. When a woman is pregnant, her body secretes human chorionic gonadotropin, a hormone that can be detected in the urine. A pregnancy test is used to determine if you are pregnant by detecting the amount of human chorionic gonadotropin in your urine. Generally, a pregnancy is signaled when there are two distinct and clear bars in the test area. In addition, a result of one dark and one light means that there is a possibility of pregnancy and only one bar means that there is no pregnancy. However, due to the quality of the pregnancy test stick, urine concentration, pregnancy time and other factors, there may be errors, resulting in false-negative or false-positive test results, so you can re-test a few days apart. Meanwhile, you can also seek medical advice for blood test, the result will be more accurate. In order to clarify whether the patient is pregnant or not, the patient should go to the regular hospital for abdominal ultrasound examination and serum HCG measurement in time to avoid misjudgment.