IVDT_In Vitro Diagnostics Technology

IVD Technology, Spring 2013

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MOLECULAR DIAGNOSTICS The Rapid Evolution of Noninvasive Prenatal Testing As the technology continues to improve, the scope of chromosomal abnormalities that can be detected will expand. BY MEGAN P. HALL 34 IVD TEC HNOL O G Y | SP RIN G 2013 magenta cyan yellow black IMAGE COURTESY NATERA T he noninvasive prenatal testing space has expanded dramatically in recent years. Tis is in large part because of breakthroughs in sequencing technologies. Te frst noninvasive prenatal test based on cell-free DNA was commercialized in October 2011 by Sequenom. Tree other tests have arrived on the market since then, including a next-generation test from Natera. Uptake of these tests by the medical community has been extremely rapid, refecting the high level of need in this area. In November 2012, the American Congress of Obstetricians and Gynecologists (ACOG) issued guidance recommending noninvasive prenatal testing for women at high risk of carrying an aneuploid fetus.1 Additionally, multiple payers, including UnitedHealthcare, Aetna, and Wellpoint, have announced medical policies in favor of noninvasive prenatal testing.2 Tese noninvasive prenatal tests all use the mixture of maternal and fetal cell-free DNA that is found in maternal plasma, which is obtained through a simple blood draw from the mother. Te cell-free DNA is amplifed then analyzed using highthroughput sequencers to detect genetic abnormalities such as trisomy 21 (Down syndrome) with high accuracy. Tis is a signifcant advance over blood-based hormone screening tests, which are safe but unreliable.3 Roughly one in six pregnancies The ability to easily obtain fetal cell–free DNA from maternal plasma and advances in sequencing technology have led to the successful commercialization of noninvasive prenatal tests. with a chromosomal abnormality will screen negative on the hormone tests. Furthermore, only one out of 16 women who screen positive using the hormone-based screening tests will actually have an afected pregnancy. Tis is concerning, since as many as one in 300 invasive procedures result in fetal loss.3 Te ability to accurately detect chromosomal abnormalities noninvasively and, thus, without risk to the fetus, both reduces the number of unnecessary invasive procedures performed to confrm screen-positive results and reduces false negative results. Research has also gone into noninvasive aneuploidy testing focusing on analysis of fetal cells. Tese eforts, however, have not reached fruition, partially because fetal cells are rare, hard to isolate, difcult to analyze, and can persist for decades, potentially complicating detection in the case of prior pregnancy.4,5 Te ability to easily obtain fetal cell–free DNA from maternal plasma,6-8 coupled with advances in sequencing technology have led to the successful and rapid commercialization of noninvasive prenatal tests. i v d t e c hnol ogy. com ES237241_IV1305_034.pgs 04.25.2013 02:08 UBM

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