How to make tang sieve
Down syndrome screening (Down syndrome screening) is one of the important prenatal tests during pregnancy, mainly used to assess the risk of the fetus suffering from Down syndrome (trisomy 21). The following will introduce the Tang Screening process, precautions and related data in detail to help expectant mothers better understand this examination.
1. What is Tang Si?
Down screening is a screening method that uses blood from pregnant women and combines it with ultrasound examination results to assess the risk of fetal Down syndrome, trisomy 18 and neural tube defects. Tang screening is divided into early pregnancy (11-13 weeks of pregnancy) and mid-term pregnancy (15-20 weeks of pregnancy).
2. Tang Sifting Process
| step | content | time |
|---|---|---|
| 1. Make an appointment for inspection | Make an appointment with the hospital or prenatal care center in advance | 11-13 weeks or 15-20 weeks of pregnancy |
| 2. Blood test | Collect venous blood from pregnant women and detect relevant indicators | Completed on the same day |
| 3. Ultrasound examination | Measure fetal nuchal translucency thickness (NT) or other indicators | On the same day as the blood draw or in advance |
| 4. Risk assessment | Combining blood and ultrasound results to calculate risk value | Results usually take 3-7 days |
3. Precautions for Tang Si
1.Time requirements are strict: Early stage screening needs to be done between 11-13 weeks of pregnancy, and mid-term screening needs to be done between 15-20 weeks of pregnancy. Missing the time may affect the accuracy of the results.
2.No need to fast: Tangsie blood drawing does not require fasting, but a light diet is recommended.
3.Interpretation of results: Tang screening results are probability assessments, not confirmed diagnoses. High-risk patients require further non-invasive DNA or amniocentesis.
4.cost: Tang screening costs vary by region and hospital, usually between 200-500 yuan.
4. Data related to Tang Si
| project | normal range | high risk threshold |
|---|---|---|
| Early Tang sieve (NT value) | ≤2.5mm | >3.0mm |
| Mid-stage screening (AFP) | 0.5-2.5MoM | >2.5MoM |
| Mid-stage screening (hCG) | 0.5-2.0MoM | >2.0MoM |
5. What should I do if Tang Si is at high risk?
If the Tang screening result is high risk, don’t be overly nervous and further examination is required:
1.Non-invasive DNA testing: Detecting fetal DNA by drawing blood from pregnant women, the accuracy is about 99%, but the cost is high (2000-3000 yuan).
2.amniocentesis: Direct detection of fetal chromosomes by extracting amniotic fluid is a diagnostic method, but there is a slight risk of miscarriage (about 0.5%).
6. Summary
Tang screening is an important screening method during pregnancy. Expectant mothers should complete the examination on time and understand the results correctly. If there is a high risk, you need to choose further examination under the guidance of a doctor to ensure the health of the fetus.
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