What is Down syndrome screening?
Down syndrome screening is a test that uses maternal blood to detect whether a fetus has Down syndrome, usually during pregnancy. Down syndrome is an intellectual disability and physical defect caused by chromosomal abnormalities. Down syndrome screening can detect abnormal amounts of chromosomes, thereby predicting whether the fetus is at risk for chromosomal abnormalities such as Down syndrome.
How do Down syndrome screening values differ between men and women?
Down syndrome screening predicts the risk of a fetus having Down syndrome by measuring the levels of three special chemicals in the mother\’s blood. These markers are free β-human chorionic gonadotropin (free β-hCG), progesterone (PAPP-A), and triphenylformamide (AFP). The titers of these substances vary according to gestational age and constitute the \”screening value\” range.
Two specific numbers in the screening score can help doctors determine whether further testing is needed. Down syndrome birth rates generally increase with high screening values. A high screening score does not mean that the child has Down syndrome, but it does mean that further testing is needed.
Interpretation of Down syndrome screening results
If the mother ends up with higher than normal test results, a further diagnosis of Down syndrome may be accompanied by a doctor\’s recommendation. For example: amniocentesis or chorionic villus tissue sampling to confirm or rule out the possibility of Down syndrome.
A high Down syndrome screening score does not necessarily mean that the child has Down syndrome, it is just an indicator of risk. If your concerns weigh the potential risks against the importance to you, especially if there is any family history of this, you may choose to seek further diagnosis. However, the screening threshold for Down syndrome is lower than for other chromosomal abnormality screenings to significantly increase the rate of non-invasive detection of chromosomal abnormalities.
Misjudgment and misdiagnosis of Down syndrome screening values
Although Down syndrome screening can accurately predict the risk of Down syndrome, misdiagnosis can still occur because not all pregnant women who have their mothers tested will actually have Down syndrome, which will lead to some false-positive results.
Since the test is done through maternal blood, mothers who have previously had too many fetuses may also have abnormal values, so they need to be evaluated on a case-by-case basis to avoid the risk of misdiagnosis.
Summary
The Down syndrome screening value is a screening test that predicts Down syndrome and can be obtained by measuring the levels of three special chemicals in the maternal blood. Down syndrome screening can detect a variety of chromosomal abnormalities, but is associated with the risk of false positives and false negatives. If the screening result is positive, then conservative measures such as further diagnosis and treatment are needed to avoid potentially having a baby with Down syndrome. However, it should be noted that the threshold for Down syndrome screening is low and cannot be used as the final diagnostic method for Down syndrome. Doctors and family members need to make decisions together to ensure appropriate results.
