The verifi® prenatal test is a non-invasive test that utilizes circulating cell-free DNA (cfDNA) extracted from a maternal blood sample taken at a minimum of 10 weeks gestation to detect fetal aneuploidy in chromosomes 21, 18 and 131.
Trisomies 21 (Down syndrome, T21), 18 (Edwards syndrome, T18), and 13 (Patau syndrome, T13) are the most common live born aneuploidies (serious conditions caused by extra chromosomes).2 Note that for all three of the above, the incidence of aneuploidy increases with maternal age.
- Trisomy 21 is the most frequently occurring of the three, occurring in, on average, one of every 740 live births.3
- Trisomy 18 occurs in about 1 in 5,000 live births.4
- Less common, Trisomy 131 occurs in approximately 1 in 7,000 to 10,000 live births.5,6
- Bianchi D et al. Genome wide fetal aneuploidy detection by sequencing of maternal plasma DNA: diagnostic accuracy in a prospective, blinded, multicenter study. AJOG Supplement. 2012 Jan; Abstract 837: S367.
- Kagan KO, Wright D, Valencia C, Maiz N, Nicolaides KH. Screening for trisomies 21, 18 and 13 by maternal age, fetal nuchal translucency, fetal heart rate, free ß-hCG and pregnancy-associated plasma protein-A. Human Reproduction. 2008; 23(9): 1968-1975.
- National Library of Medicine. Down syndrome. Available at: http://ghr.nlm.nih.gov/condition/down-syndrome. Accessibility verified January 23, 2012.
- National Library of Medicine. Trisomy 18. Available at: http://ghr.nlm.nih.gov/condition/trisomy-18. Accessibility verified January 23, 2012.
- Savva GM, Walker K, Morris JK. The maternal age-specific live birth prevalence of trisomies 13 and 18 compared to trisomy 21 – (Down syndrome). Prenatal Diagnosis. 2010; 30: 57-64.
- National Library of Medicine. Trisomy 13. Available at: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002625/.
- Source on file with Verinata.
The verifi® test is intended for use in women 18 years or older with a singleton pregnancy at a minimum of 10 weeks gestation and who have been determined by their physician to be at risk for fetal trisomy. Indications for increased risk for fetal trisomy include advanced maternal age, positive results of prenatal screening tests (serum and/or NT ultrasound), presence of ultrasound soft or hard markers, previous family history of genetic disorders, or a previous affected pregnancy for fetal aneuploidy. The test can be performed in the 1st or 2nd trimester of pregnancy.
The verifi® prenatal test utilizes cell-free DNA (cfDNA) from both the patient and fetus. Patient plasma contains more than enough fetal fragments for our test. Each sample is sequenced with millions of short reads. The reads are aligned to the human genome and counted using our proprietary SAFeR™ (Selective Algorithm for Fetal Results) method. Our CLIA lab then analyzes and classifies the sample.
- Bianchi D et al. Genome-wide Fetal Aneuploidy Detection by Maternal Plasma DNA Sequencing. Obstet Gynecol. 2012 May; 119(5). Published ahead of print:
- Available at http://clinicaltrials.gov/ct2/show/NCT01122524.