Early pregnancy test is used to determine if you are pregnant by detecting the HCG concentration in human urine, which can usually be detected 10-14 days after conception. After intercourse, if the sperm and egg are successfully united, 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. The correct use of a pregnancy test paper can give quick results, i.e. the test is done by taking the middle part of the morning urine, placing it in a clean urine cup, soaking one end of the test paper in the urine and checking the result after 3-5 minutes. One bar means you are not pregnant; two bars of the same color means you are pregnant; if two bars are dark and one is light, it is recommended to test again in 3 days. In addition, early pregnancy test strips may sometimes give false positive results, so it is most accurate to check whether you are pregnant or not by ultrasound examination.