The value of HCG in children with Down’s syndrome may be normal. The normal value is between 0.3 and 2.5, and some may be higher. In clinical practice, HCG can only be used for screening and not for diagnosis. If a woman wants further testing, she can undergo a Down’s syndrome screening test, which is performed by taking the blood of a pregnant woman and checking the level of certain substances in the blood serum to make a determination. There are three types of Down’s syndrome screening results, one is high risk, one is low risk, there is also a critical value, the accuracy of the Down’s syndrome screening test is relatively high, there is another test is to be diagnosed through amniocentesis or chorionic villus test, the accuracy of the test is higher than the accuracy of the Down’s syndrome screening test, can reach more than 90%.