Girls, hello everyone. Who has done the second prenatal screening? I…

Girls, hello everyone. Who has done the second prenatal screening? I took it at 17.6 weeks. The AFP normal for 17th week is indicated as 33. But I took it practically at 18th week. In the end, the AFP was 37.5. It says that the elevated value. Besides, there's chorionic gonadotropin human with B subunit. Normal median is 0.5-2.0. My 0.48. I don't know if there is a difference that I took practically at 18th week (a day earlier). And they put 17th week.