Usually, if a woman has a chorionic gonadotropin test <0.1 u/ml, this is a sure sign that she is not pregnant. This is because usually the minimum reference value for chorionic gonadotropin is within 0u/ml-5u/ml, or 0u/ml-10u/ml, or even 0u/ml-25u/ml, regardless of the hospital test department, so a detected chorionic gonadotropin <0.1u/ml is indicative of no pregnancy at all. However, to detect chorionic gonadotropin, you must go to the hospital gynecology department 11 days after the last intercourse to have your blood drawn to be accurate, if you go to the hospital to check this hormone just after 2-3 days of intercourse, it will not be detected at all.