Noninvasive prenatal testing: limitations and unanswered questions.

The clinical use of noninvasive prenatal testing to screen high-risk patients for fetal aneuploidy is becoming increasingly common. Initial studies have demonstrated high sensitivity and specificity, and there is hope that these tests will result in a reduction of invasive diagnostic procedures as well as their associated risks. Guidelines on the use of this testing in clinical practice have been published; however, data on actual test performance in a clinical setting are lacking, and there are no guidelines on quality control and assurance. The different noninvasive prenatal tests employ complex methodologies, which may be challenging for health-care providers to understand and utilize in counseling patients, particularly as the field continues to evolve. How these new tests should be integrated into current screening programs and their effect on health-care costs remain uncertain.