and CVS are currently the most commonly used tests to diagnose fetal and chromosomal malformations.
These are tests capable of making a certain diagnosis, while the
nuchal and the bi and tri-test are probabilistic only (
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However, amniocentesis is a test
and not without risks, it is calculated, in fact, that there is a risk percentage of
between 0.2 and 1%.
However, there is also another non-invasive and in any case effective way to diagnose the presence of Trisomies 13, 18 and 21 (responsible for Down syndrome) in the genetic makeup of the fetus.
This is the
a blood test taken from the maternal vein in a harmless and simple way.
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How does this test work?
It can be done starting from
of pregnancy with a simple
of mom’s blood. The results, generally ready within two weeks, reveal the presence of the most common chromosomal anomalies, 13, 18 and 21.
The accuracy of this exam, which is performed for a fee, would be nearly 100 percent.
However, with respect to amniocentesis (
), the Preana Test cannot diagnose other less common chromosomal abnormalities and the result may not be reliable in case of
The expectant mother can undergo the Preana test (as well as amniocentesis) where previous ultrasound or biochemical tests, such as nuchal translucency and bitest, have shown a high probability of
or belongs to risk groups (e.g. previous family anomalies).