Down syndrome screening (Down syndrome screening)It is a prenatal screening method mainly used to assess the risk of fetal Down syndrome (trisomy 21) and other chromosomal abnormalities.Its core content includesScreening principles, detection methods, applicable populations, result interpretation and limitations.In terms of primary and secondary structure, screening principles and detection methods are the focus, followed by applicable populations and result interpretation, and limitations are supplementary explanations.

Tang sieve passedMaternal serum marker testing(such as AFP, hCG, etc.) combined with ultrasound examination (such as NT value measurement) to comprehensively calculate the risk of fetal chromosomal abnormalities.Screening is divided intoEarly (11-13 weeks of pregnancy) and second trimester (15-20 weeks of pregnancy)There are two stages, the early stage is based on NT ultrasound + serum, and the mid stage is based on serological screening.This method is non-invasive and safe, but it is only a risk assessment and cannot confirm the diagnosis.

Tang sieve is suitable forall pregnant women, it is especially recommended for people over 35 years old, with a family history of hereditary disease or a history of adverse pregnancy and childbirth.Screening results are usuallyRisk value (such as 1/1000)It appears that high-risk cases require further diagnosis through amniocentesis or non-invasive DNA.It should be noted that Tangsie existsFalse positive rate (about 5%), may cause unnecessary anxiety, and should be viewed rationally and in conjunction with doctor’s advice.

In terms of limitations, Tangsi can only detect60%-90%of Down syndrome cases and cannot cover all chromosomal abnormalities.In contrast,Non-invasive DNA testing is more accurate (>99%), but the cost is higher.Therefore, pregnant women whose financial conditions permit can consider choosing non-invasive testing directly, while Tang screening is still widely used as a basic screening method.

In summary, Tang screening is an important part of prenatal care.Economical and popularThe advantages are obvious, but they need to be clarifiedScreening rather than diagnosisproperties.Pregnant women should choose an appropriate plan based on their own circumstances and with the guidance of a doctor to avoid the psychological burden caused by misunderstanding the results.Only by scientifically understanding the applicable scope and limitations of Tangsiine can we maximize its health management value.

Quote sources:
1. Chinese Medical Association's "Guidelines for Pre-Pregnancy and Pregnancy Health Care (2022)"
2. American College of Obstetricians and Gynecologists (ACOG) "Guidelines for Prenatal Screening"
3. Expert opinion: Professor Ma Liangkun, Director of the Obstetrics Department of Peking Union Medical College Hospital, discusses the clinical significance of Tang screening