After intercourse, if conception is successful, early pregnancy test strips can usually detect a positive result 7 to 10 days after conception. The full name of early pregnancy test paper is human chorionic gonadotropin (HCG) test paper, which is used to detect HCG in human urine to assist in diagnosing whether a woman is pregnant. When the HCG level in urine reaches 25mIU/ml or higher, a positive test result is obtained, which indicates the possibility of pregnancy. A positive test result is usually obtained 7 to 10 days after successful conception. If the test is negative, but there is a high suspicion that conception is possible, the test can be repeated 48 to 72 hours later by re-collecting morning urine. Early pregnancy test strips should be used as soon as possible after opening the sealed bag to avoid moisture affecting the results. When the HCG concentration is very high, the color of the test line may become lighter, which is normal. In addition, false positives may occur if there is a high level of HCG in the urine, such as in patients with uterine tumors, hyperemesis gravidarum, endometrial hyperplasia, choriocarcinoma, and gastric cancer. Early pregnancy test paper is only used to assist in determining whether you are pregnant or not, if you want to make a clear diagnosis, you need to go to the hospital and combine with other tests to determine.