Prenatal Diagnosis Flashcards
Describe the differences between screening tests and diagnostic tests.
• Screening:
- assess risk
- quick
- high NPV
- low FPs
•Diagnostic:
- can run in or out
- longer
- usually definitive
In general, prenatal screening is not for patients ____________.
who do not want to know; who would not accept results; who would not change anything for the family or for the medical management
We don’t make management decisions on ___________ results.
screening
Maternal blood tests for cell-free fetal DNA is considered a ______________.
screening test
To ensure their safety, ultrasounds have sensors telling you if ____________.
you’ve been in one place too long (which could theoretically heat fluids)
The most important use of the first-trimester ultrasound is ________________.
to determine the due date
_______________ (which can be determined by vaginal ultrasound) is predictive of preterm delivery.
Cervical length
The gestational sac is only measured during ____________.
the first trimester (when the fetus is too small to be meaningfully measured)
The best indicator of gestational age and growth during the second trimester is _________.
the averaged percentiles of multiple measurements (femur, skull, etc.)
Generally, NTDs present with elevated ________.
AFP
Trisomy 18 presents with what abnormal serum analytes?
Decreased levels of everything: AFP, hCG, inhibin A, and PAPP
Trisomy 21 presents with low _________ and elevated ___________.
AFP; hCG and inhibin A
Currently, the best screening test for Down syndrome is _______________.
cell-free DNA
Where is AFP made?
In the fetal liver
In general, ultrasounds can more accurately determine age when ____________.
they’re done earlier in the pregnanccy
