Product News: Clinical Utility of Non-Invasive Harmony Prenatal Test Demonstrated in New Study

11 Sep 2012

A study just published in the American Journal of Obstetrics and Gynecology (The Gray Journal) provides substantial new evidence that the Harmony Prenatal Test, a specific type of non-invasive prenatal test (NIPT), is effective in a general screening population. In this study, the test detected all cases of fetal trisomy 21 and 18 at a false-positive rate of 0.1 percent.

The study, “Noninvasive Prenatal Testing for Fetal Trisomies in a Routinely Screened First-Trimester Population,” was led by Dr. Kypros H. Nicolaides, professor at the Harris Birthright Research Centre for Fetal Medicine at King’s College Hospital in London, with fellow authors Argyro Syngelaki, Dr. Ghalia Ashoor, Dr. Cahit Birdir and Dr. Gisele Touzet.

The Harmony test is a type of NIPT utilizing a directed approach to cell-free DNA (cfDNA) analysis and provides an individualized risk assessment for trisomy (the presence of three chromosomes instead of two). It involves a single blood draw taken as early as 10 weeks’ gestation and delivers a greater than 99 percent detection rate for trisomy 21, which causes Down syndrome. Much of the research on NIPT to date has focused on women determined to be at a high-risk for trisomy.

“This excellent study validates the detection of fetal trisomy through analysis of maternal plasma using chromosome-selective, cell-free fetal DNA sequencing in an average-risk population. False positive diagnoses were rare (2 per 1949), but the few encountered indicate that invasive procedures are still necessary on occasion for confirmation,” said Dr. Joe Leigh Simpson, senior vice president for Research and Global Programs at the March of Dimes. He added, “False positive results could be due either to confined placental mosaicism or to unrecognized demise of an aneuploidy co-twin. Overall, it is clear that cell-free fetal DNA analysis is becoming the preferable method for fetal aneuploidy screening.”

The study builds on other recent findings that support the utility of NIPT for any pregnant woman, regardless of risk categorization. Other studies have shown no significant differences in the fraction of fetal cfDNA in blood in women based on maternal age, prenatal screening results or nuchal translucency measurement. The amount of fetal cfDNA in maternal blood is the principal factor in successfully detecting trisomies with NIPT.

“This study affirms our commitment to leading the introduction of NIPT into medical practice based on robust clinical data. We have now studied over 6,000 women including 2,000 low risk women across multiple studies,” said Ariosa Diagnostics CEO Ken Song, MD. “The Harmony Prenatal Test represents a major advance in obstetrics that can provide highly accurate information to women so as to better manage their pregnancy.”