The pregnancy test can detect pregnancy, but not ectopic pregnancy. It is a qualitative test for positive urine HCG. A small amount of urine is infiltrated into the test area of the pregnancy test and if two red lines appear, it is positive, indicating pregnancy, and if one line appears, it is negative, indicating no pregnancy. In other words, the pregnancy test can detect that the egg and sperm meet to form a fertilized egg and secrete HCG (human chorionic gonadotropin), but the amount of HCG secreted, whether the fertilized egg has laid or not, and whether it has laid in the uterus or outside the uterus are unknown, so ectopic pregnancy cannot be detected by the pregnancy test. Clinically, the diagnosis of ectopic pregnancy is made by combining the blood HCG value with vaginal ultrasound. When the blood HCG value is >2000iu/l and the intrauterine fetal sac is not detected by vaginal ultrasound, the diagnosis of ectopic pregnancy is basically established. HCG, the full name of which is human chorionic gonadotropin, is secreted by the syncytial trophoblast cells of the placental chorionic membrane starting 10-14 days after conception and is the most sensitive method for the diagnosis of early pregnancy; it is essential for the early diagnosis of ectopic pregnancy; in short, HCG levels are lower in ectopic patients than in normal intrauterine pregnancies. In fact, it is difficult to determine ectopic pregnancy on the basis of a particular blood HCG value; in other words, there is no standardized HCG value for ectopic pregnancy. For a normal intrauterine pregnancy, the blood HCG level should increase at a rate of 66% per day between 6 and 8 weeks of gestation. If the growth rate of the blood HCG level is less than 66% in 48 hours, it indicates a poor post-pregnancy period. Therefore, if the doubling time of the blood HCG value is less than 1.4 days, ectopic pregnancy is very unlikely (if the doubling time of the blood HCG value is less than 1.4 days, ectopic pregnancy is basically not considered).