Physician's Corner

We are please to offer you a new option for non-invasive maternal serum testing that has been receiving attention in the media including such publications as the New York Times.

The MaterniT21 test is a cell-free fetal nucleic acid test for trisomy 21 (Down syndrome), developed by Sequenom®.  This test has been clinically validated in a population of pregnant women with increased risk for fetal Down syndrome based on advanced maternal age, ultrasound abnormalities, positive serum screening and/or a family history of Down syndrome.  Clinical validation studies found a 99.1% sensitivity and a 99.9% specificity.¹  Maternal blood can be drawn for this test beginning at 10 weeks gestation and results are typically available in 10-14 days.  Currently, the MaterniT21 test does not screen for other aneuploidies and is not a replacement for CVS/amniocentesis.  A negative MaterniT21 test can be used to significantly reduce a patient’s a priori risk for Down syndrome (a 72-fold risk reduction was reported). If a MaterniT21 result returns positive, CVS or amniocentesis is recommended for definitive diagnosis.  

Based on the current published data, San Francisco Perinatal Associates will offer MaterniT21 testing to those women that meet the following criteria:

• Advanced Maternal Age
• Ultrasound abnormality suggestive of Down syndrome
• Positive California Prenatal Screen for Down syndrome
• Family history of Down syndrome
  

It is important to know the following:

• MaterniT21 testing must be run in conjunction with the California Prenatal Screen
• MaterniT21 has not been validated in multiple gestations and is not recommended to women carrying a multiple gestation
• MaterniT21 has not been validated in low risk pregnancies and is not recommended to those women that do not meet the inclusion criteria
  

Given the complexity of this testing, San Francisco Perinatal Associates strongly recommends genetic counseling prior to testing. This is not currently considered a standard testing option. Given the number of requests that we had already received, SFPA has decided to offer this option to women who meet the testing criteria and have completed the genetic counseling process.

If you or your patients have questions regarding MaterniT21, please contact our office at 415-202-1200.


James Goldberg, MD, Michael Katz, MD, Melinda Scully, MD,
Per Sandberg, MD, Susan Fong, MD


¹ Palomaki GE, Kloza EK, Lambert-Messerlian GM, et al. DNA sequencing of maternal plasma to detect Down syndrome:an international clinical validation study. Genetics in Medicine 2011;13:913-920.