It takes 2-3 days for the sperm to enter the woman’s body and meet the egg in the abdomen of the fallopian tube and form a fertilized egg, then it takes about 7 days to complete the process of implantation and the HCG level in the body gradually increases to a measurable concentration. It is best to go to the hospital in the morning on an empty stomach to have a blood test for human chorionic gonadotropin, the test results will be available on the same day, or you can arrange to go to the hospital at any time according to your personal situation and time. If you have a regular menstrual cycle and your period is delayed for more than 7 days after having sex without safety measures, you should also go to the hospital for a blood test for HCG and progesterone levels.