The early pregnancy test determines if you are pregnant by checking the HCG concentration in your body’s urine and can usually be detected 10-14 days after intercourse. If the sperm unites with the egg after intercourse, the fertilized egg will be laid in 6-7 days and the chorionic gonadotropin in the body will rise rapidly, doubling on average every 48 hours or so. A blood test for chorionic gonadotropin can be taken 10 days after intercourse to determine if you are pregnant. A low concentration of chorionic gonadotropin in the urine will detect pregnancy a little later, usually at 10-14 days. In addition, women should take the middle part of their morning urine and put it in a clean urine cup, soak the end of the test strip in the urine and check the result after 3-5 minutes. One bar means no pregnancy; two bars of the same color means pregnancy; if two bars are dark and one is light, it is recommended to test again after 3 days.