Noninvasive prenatal testing for fetal aneuploidy: clinical assessment and a plea for restraint.

The recent introduction of clinical tests to detect fetal aneuploidy by analysis of cell-free DNA in maternal plasma represents a tremendous advance in prenatal diagnosis and the culmination of many years of effort by researchers in the field. The development of noninvasive prenatal testing for clinical application by commercial industry has allowed much faster introduction into clinical care, yet also presents some challenges regarding education of patients and health care providers struggling to keep up with developments in this rapidly evolving area. It is important that health care providers recognize that the test is not diagnostic; rather, it represents a highly sensitive and specific screening test that should be expected to result in some false-positive and false-negative diagnoses. Although currently being integrated in some settings as a primary screening test for women at high risk of fetal aneuploidy, from a population perspective, a better option for noninvasive prenatal testing may be as a second-tier test for those patients who screen positive by conventional aneuploidy screening. How noninvasive prenatal testing will ultimately fit with the current prenatal testing algorithms remains to be determined. True cost-utility analyses will be needed to determine the actual clinical efficacy of this approach in the general prenatal population.