Down syndrome is a major disease that affects fetuses, and Down screening is a prenatal screening examination for Down syndrome. It is a method of testing the blood of pregnant women, using technological means to detect the concentrations of alpha fetoprotein, chorionic gonadotropin, and free estriol in the maternal serum, and combining other characteristics of pregnant women such as age, weight, gestational age, etc. to determine the risk of fetal diseases such as Down syndrome and neural tube defects. There is a reference range for the coefficient of Down syndrome screening, so what is the normal ratio for Down syndrome screening?
What is the normal ratio for Tang screening
The inspection reference standards provided by different testing institutions are different. There is no accurate value for Down syndrome screening, only a proportion. The specific situation should be based on the inspection report. The following are several common numerical ranges.
1. Critical value
The critical range is 1/250-1/380. Pregnant women within this range should be vigilant and preferably retested to determine if early intervention is needed.
2. Normal value
The normal value is around 1/700. Those with values lower than this should rest assured that the probability of developing Down syndrome is very low, so there is no need to panic.
3. High risk value
When the blood test screening value is greater than 1/270, it is considered a high-risk value and further testing should be carried out. It is important to follow the doctor's advice in a timely manner. It is worth noting that the results of Down syndrome screening only provide a risk coefficient, which does not necessarily mean that high-risk babies have problems. Cooperate with the doctor to do a good examination, see how high the risk of illness is, and then decide on measures to be taken.
How to further diagnose Down syndrome through screening
If the test result is high-risk, it is best to screen once. Firstly, pay attention to the screening time, which is between 15-20 weeks of pregnancy. There are several medical methods that can further confirm the diagnosis.
1. Amniocentesis
Amniotic fluid aspiration is a common testing method nowadays, but it also carries certain risks, such as the possibility of causing intrauterine infection, and in severe cases, miscarriage.
2. Non invasive DNA testing
This technology is currently a relatively advanced detection method, with a relatively high success rate and low relative risk.
The screening result of Down syndrome is only a risk factor, and the value of the examination is only a prediction of the probability of disease occurrence. The final result still needs to be diagnosed through scientific means. To carry out scientific pregnancy preparation, it is necessary to have balanced nutrition, stay away from all factors that may cause fetal diseases, and follow the guidance and advice of doctors. The best approach is to promptly identify risks and adopt scientific methods for treatment.
