To the Point– cfDNA is a screening test, whereas amniocentesis and CVS are considered diagnostic tests. Although sensitivity and specificity are quite high for certain conditions, cfDNA CANNOT be substituted for diagnostic testing such as amniocentesis in terms of the degree of certainty associated with the results.
|Noninvasive Prenatal |
|Chorionic Villus |
|Risks||No risk of miscarriage||<1% risk of miscarriage||<1% risk of miscarriage|
|Results||Increased or decreased risk level; NOT "yes or no" answers. NIPT is based on assessing DNA from placental cells, not fetal cells.||Typically "yes or no" results with high level of accuracy. |
CVS looks at placental cells versus fetal cells which does increase chances of false positive results or need for further testing.
|Typically "yes or no" results with high level of accuracy. Amniocentesis looks directly at fetal cells.|
|Timing||Approximately 10 weeks and beyond||Approximately 10-14 weeks||Approximately 15-20 weeks (can be done later)|
|Routinely screens for Down syndrome, Trisomy 13 & Trisomy 18 and may screen for other conditions depending on preference and laboratory.||Much more comprehensive testing. Routinely assesses all chromosomes.||Much more comprehensive testing. Routinely assesses all chromosomes.|
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