国际母胎医学会遗传学专业委员会(Committee on Genetics, Society for Maternal–Fetal Medicine)针对利用游离胎儿DNA筛查非整倍体(cell-free DNA screening for fetal aneuploidy)的建议。
The American College of
Obstetricians and Gynecologists
WOMEN’S HEALTH CARE PHYSICIANS
COMMITTEE OPINION
Number 640 September 2015 Committee on Genetics
Society for Maternal–Fetal Medicine
This document reflects emerging clinical and scientific advances as of the date issued and is subject to change. The information should
not be construed as dictating an exclusive course of treatment or procedure to be followed.
(This Committee Opinion Replaces Committee Opinion Number 545)
Cell-free DNA Screening for Fetal Aneuploidy
ABSTRACT: Noninvasive prenatal screening that uses cell-free DNA from the plasma of pregnant women offers tremendous potential as a screening method for fetal aneuploidy. A number of laboratories have validated different techniques for the use of cell-free DNA as a screening test for fetal aneuploidy. All tests have a high sensitivity and specificity for trisomy 18 and trisomy 21, regardless of which molecular technique is used. Women whose results are not reported, indeterminate, or uninterpretable (a “no call” test result) from cell-free DNA screening should receive further genetic counseling and be offered comprehensive ultrasound evaluation and diagnostic testing because of an increased risk of aneuploidy. Patients should be counseled that cell-free DNA screening does not replace the precision obtained with diagnostic tests, such as chorionic villus sampling or amnio-centesis and, therefore, is limited in its ability to identify all chromosome abnormalities. Cell-free DNA screening does not assess risk of fetal anomalies such as neural tube defects or ventral wall defects. Patients who are undergoing cell-free DNA screening should be offered maternal serum alpha-fetoprotein screening or ultrasound evaluation for risk assessment. The cell-free DNA screening test should not be considered in isolation from other clinical findings and test results. Management decisions, including termination of the pregnancy, should not be based on the results of the cell-free DNA screening alone. Patients should be counseled that a negative cell-free DNA test result does not ensure an unaffected pregnancy. Given the performance of conventional screening methods, the limitations of cell-free DNA screening performance, and the limited data on cost-effectiveness in the low-risk obstetric population, conventional screening methods remain the most appropriate choice for first-line screening for most women in the general obstetric population.
Recommendations
A discussion of the risks, benefits, and alternatives of
various methods of prenatal screening and diagnostic testing, including the option of no testing, should occur with all patients.
Given the performance of conventional screening
methods, the limitations of cell-free DNA screen-ing performance, and the limited data on cost-effectiveness in the low-risk obstetric population, conventional screening methods remain the most appropriate choice for first-line screening for most women in the general obstetric population.
Although any patient may choose cell-free DNA anal-ysis as a screening strategy for common aneuploidies regardless of her risk status, the patient choosing this testing should understand the limitations and benefits
of this screening paradigm in the context of alterna-tive screening and diagnostic options.
The cell-free DNA test will screen for only the com-mon trisomies and, if requested, sex chromosome composition.
Given the potential for inaccurate results and to
understand the type of trisomy for recurrence-risk counseling, a diagnostic test should be recommended for a patient who has a positive cell-free DNA test result.
Parallel or simultaneous testing with multiple
screening methodologies for aneuploidy is not cost- effective and should not be performed.
Management decisions, including termination of the
pregnancy, should not be based on the results of the cell-free DNA screening alone.
VOL. 126, NO. 3, SEPTEMBER 2015 OBSTETRICS & GYNECOLOGY e31
国际母胎医学会遗传学专业委员会(Committee on Genetics, Society for Maternal–Fetal Medicine)针对利用游离胎儿DNA筛查非整倍体(cell-free DNA screening for fetal aneuploidy)的建议。
Women whose results are not reported, indeter-minate, or uninterpretable (a “no call” test result)
from cell-free DNA screening should receive further genetic counseling and be offered comprehensive ultrasound evaluation and diagnostic testing because of an increased risk of aneuploidy.
Routine cell-free DNA screening for microdeletion
syndromes should not be performed.
Cell-free DNA screening is not recommended for
women with multiple gestations.
If a fetal structural anomaly is identified on ultra-
sound examination, diagnostic testing should be offered rather than cell-free DNA screening. Patients should be counseled that a negative cell-free DNA test result does not ensure an unaffected