Question 1

Which of the following statements best describes the main difference between prenatal genetic screening and diagnostic testing?

Accepted Answer

Screening tests estimate the risk of a genetic condition, whereas diagnostic tests confirm the presence or absence of a condition.

Question 2

A pregnant patient receives a positive result from a first trimester serum screening for Down syndrome. What is the next recommended step according to current guidelines?

Accepted Answer

Perform a diagnostic test such as chorionic villus sampling (CVS) or amniocentesis to confirm the diagnosis.

Question 3

Which of the following is NOT a common indication for offering prenatal genetic screening to a pregnant woman?

Accepted Answer

Presence of gestational diabetes

Question 4

Which equation correctly represents the calculation of positive predictive value (PPV) for a prenatal screening test?

Accepted Answer

$$PPV = \frac{True\ Positives}{True\ Positives + False\ Positives}$$

Question 5

A couple is considering non-invasive prenatal testing (NIPT) for chromosomal abnormalities. Which of the following statements about NIPT is correct?

Accepted Answer

NIPT analyzes fetal DNA obtained from maternal blood and is highly sensitive for detecting trisomy 21.

Question 6

Which of the following is a limitation of first trimester ultrasound screening for chromosomal abnormalities?

Accepted Answer

It may miss some cases of Down syndrome if nuchal translucency is not increased.

Question 7

A patient receives a negative result from a prenatal screening test for trisomy 18. What does this result indicate?

Accepted Answer

The risk of trisomy 18 is low, but the condition cannot be ruled out completely.

Question 8

Which of the following prenatal diagnostic procedures is considered invasive?

Accepted Answer

Chorionic villus sampling (CVS)

Question 9

A woman with a previous child affected by a chromosomal abnormality is pregnant again. What is the most appropriate genetic testing strategy for her current pregnancy?

Accepted Answer

Recommend both screening and diagnostic testing, such as NIPT and amniocentesis.

Question 10

Which of the following best explains why positive predictive value (PPV) of a screening test is higher in high-risk populations?

Accepted Answer

Because the prevalence of the condition is higher, increasing the proportion of true positives among those who test positive.

Question 11

Which of the following is a key ethical consideration in offering prenatal genetic screening?

Accepted Answer

Ensuring that patients are fully informed about the benefits, limitations, and possible outcomes of testing.

Question 12

A first trimester ultrasound reveals increased nuchal translucency (NT) in a fetus. Which of the following conditions is most strongly associated with this finding?

Accepted Answer

Trisomy 21 (Down syndrome)

Question 13

Which formula correctly calculates the sensitivity of a prenatal screening test?

Accepted Answer

$$Sensitivity = \frac{True\ Positives}{True\ Positives + False\ Negatives}$$

Question 14

A patient is found to have a high-risk result on a combined first trimester screening (serum markers and NT ultrasound). What is the most appropriate next step?

Accepted Answer

Offer diagnostic testing such as CVS or amniocentesis.

Question 15

Which of the following is a reason why non-invasive prenatal testing (NIPT) is increasingly preferred over traditional serum screening?

Accepted Answer

NIPT has higher sensitivity and specificity for common chromosomal abnormalities.

Question 16

Which of the following best describes the role of ultrasound in prenatal genetic screening?

Accepted Answer

Ultrasound is a powerful screening tool that can identify structural abnormalities and increase risk stratification for chromosomal defects.

Question 17

A woman with no known risk factors for genetic disorders is offered prenatal screening. What is the primary purpose of this screening?

Accepted Answer

To estimate the risk of common chromosomal abnormalities such as trisomy 21.

Question 18

Which of the following is a potential psychological impact of prenatal genetic screening on expectant parents?

Accepted Answer

Increased anxiety and emotional stress due to uncertain or high-risk results.

Question 19

A patient asks about the accuracy of prenatal screening tests. Which statement is most accurate?

Accepted Answer

Screening tests estimate risk and may have false positives and false negatives; diagnostic tests are needed for confirmation.

Question 20

Which of the following is a real-world example of a prenatal diagnostic procedure used to confirm a chromosomal abnormality detected by screening?

Accepted Answer

Amniocentesis to analyze fetal karyotype for trisomy 21.

Prenatal Genetic Screening and Testing: Current Landscape

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