Simple, safe test

The verifi Prenatal Test is performed by Verinata Health, Inc., a wholly owned subsidiary of Illumina
and is a noninvasive prenatal test that screens for multiple fetal chromosomal aneuploidies using a single maternal blood draw. The basic verifi Test screens for T21 (Down syndrome), T18 (Edwards syndrome), and T13 (Patau syndrome).

  • Safe—Routine, noninvasive blood draw, just one tube (7–10 ml)
  • Accurate—Directly analyzes cell-free fetal and maternal DNA with our proprietary SAFeR algorithm
  • Easy—Test as early as 10 weeks gestational age (8 weeks of fetal age as determined by date of conception). No limitations in reference to ethnicity, BMI, ART or egg donor cases
  • Fast—Results reported to partner laboratory in 3 - 5 business days after sample receipt. (Time to report may vary in times of exceptional demand.) 

Noninvasive prenatal testing (NIPT) helps reduce the need for invasive procedures View Webinar

verifi Prenatal Test provides informative NIPT results

The verifi Prenatal Test takes advantage of deep massively parallel sequencing across the genome, to provide clearer resolution for highly sensitive and specific answers.

  • Fast time to report (3 - 5 business days after sample receipt, may vary in times of exceptional demand)
  • Validation, clinical experience, and analytic studies published in multiple peer-reviewed journals

Test Performance Metrics

Test performance metrics are essential both before and after patients undergo prenatal aneuploidy screening.

Performance Metrics Considerations Before Screening

Sensitivity and Specificity

A test’s sensitivity and specificity can help healthcare providers:

  • Decide which prenatal screening option(s) to offer their patients
  • Determine which laboratory to use
  • Counsel patients about benefits and limitations of the aneuploidy screening options

Table 1. verifi Sensitivity and Specificity for Chromosomes 21, 18 and 131

Chromosome Samples Analyzed Sensitivity 95% CI Specificity 95% CI
21 500 >99.9%
96.0–100.0 99.8%
18 501 97.4%
86.2–99.9 99.6%
13 501 87.5%
61.7–98.5 >99.9%

Table 2. verifi Sensitivity and Specificity for XX, XY and Monosomy X (MX)1

Sex Chromosome Classification Number Analyzed Sensitivity 95% CI Specificity 95% CI Accuracy 95% CI
XX 508 97.6%
94.8-99.1 99.2%
97.2-99.9 98.4% 96.9-99.3
XY 508 99.1%
96.9-99.9 98.9%
96.9-99.8 99.0% 97.7-99.7
MX 508 95.0%
75.1–99.9 99.0%
97.6–99.7 N/A N/A

Sensitivity and specificity are test specific, not patient specific. As such, they are not expected to change significantly based on an individual patient’s clinical picture (e.g. maternal age, ultrasound findings, etc)

Performance Metrics Considerations After Screening

Positive Predictive Value (PPV)

A test’s PPV can help you determine how likely a positive result is to be a true positive versus a false positive.

PPV is based on the sensitivity and specificity of the test AND the prevalence of the condition in the population being tested.

Why Prevalence Matters for PPVs

  • Since the prevalence of autosomal trisomies (e.g. trisomy 21) increases with maternal age, so do the PPVs.
  • Trisomy 21 is the most prevalent autosomal trisomy in livebirths. Thus, the PPVs are higher for trisomy 21 than for trisomies 18 and 13, which are less common.

PPVs calculated using verifi sensitivities and specificities1 and the published prevalence estimates of trisomy 21, trisomy 18, and trisomy 13 at 10 weeks gestation for different maternal ages2.

  • The PPVs above are calculated based solely on age-related prevalence; the presence of other aneuploidy risk factors (e.g. ultrasound abnormalities) would likely increase the PPV over those shown here.

Why Specificity Matters for PPVs

  • While the PPVs are lower for younger women, it is important to remember that regardless of maternal age, PPVs for NIPT will be higher than those of traditional serum screening because NIPT has significantly higher specificity (a lower false positive rate)3.

PPVs calculated using verifi and first trimester combined screening sensitivities and specificities1,4 and published prevalence estimates of trisomy 21, trisomy 18, and trisomy 13 at 10 weeks gestation for different maternal ages2.

For patients with a positive NIPT result:

  • To calculate a patient’s individual PPV, you may wish to use the PPV calculator endorsed by ACOG5
  • Counsel the patient about the NIPT results, the likelihood of a true positive (PPV), and the recommendation for confirmatory diagnostic testing6


1 Illumina. Analytical Validation of the verifi prenatal test: Enhanced Test Performance for Detecting Trisomies 21, 18, and 13 and the Option for Classification of Sex Chromosome Status. Illumina White Paper. 2012.
2 Gardner RJM, Sutherland GR, Shaffer LG. Parental age counseling and screening for fetal trisomy. Chromosome abnormalities and genetic counseling. 4 ed: Oxford University Press; 2012:403-416.
3 Bianchi DW, Parker RL, Wentworth J, et al. DNA sequencing versus standard prenatal aneuploidy screening. N Engl J Med. 2014;370(9):799-808.
4 Nicolaides KH. Screening for fetal aneuploidies at 11 to 13 weeks. Prenat Diagn. 2011;31(1):7-15.
5 The American Congress of Obstetricians and Gynecologists. NIPT Cell Free DNA Screening Predictive Value Calculator. National Society of Genetic Counselors (NSGC) and Perinatal Quality Foundation (PQF). Endorsed December 2015. 2015; Accessed January 28, 2015.
6 Committee Opinion No. 640: Cell-free DNA Screening for Fetal Aneuploidy. Obstet Gynecol. 2015;126(3):e31-37.

Screening twin pregnancies

Screening for fetal aneuploidy in twin gestations poses unique challenges such as lower levels of DNA available for analysis from each fetus. By expanding the sensitivity and overall capability of the assay, the verifi Prenatal Test is available for use in twin pregnancies.  For  twin pregnancies, the verifi Test screens for T21, T18, T13 and the presence of Y chromosome (optional).  The verifi Test can be used in both monozygotic and dyzygotic pregnancies."


Innovative developments in workflow and bioinformatics have led to improved accuracy in classifying aneuploidy-affected samples.  Using our improved algorithm to analyze 115 maternal plasma samples from twin pregnancies, the twins option correctly screened.3

  • 3/3 cases with T21 present in one twin
  • 1/1 case with T18 present in both twins (monochorionic)
  • 91/91 cases with at least one male twin
  • No false positives reported in this data set.

4Verinata Health, Inc (2012) Accurate Aneuploidy Detection in Twin Pregnancies with an Optimized Algorithm for the verifi Prenatal Test. Redwood City, CA.

How the process works

Test requisition/signed consent form and blood sample are obtained

Blood sample and test request form are sent back to the lab

The lab processes and analyzes the sample

The lab reports test results

Illumina genetic counselors are available to provide guidance on laboratory results.

Our products

verifi Prenatal Test

  • Screens for T21 (Down syndrome), T18 (Edwards syndrome), and T13 (Patau syndrome)
  • The sex chromosome test option for singleton pregnancies screens for monosomy X (MX)
  • For twin pregnancies, the presence of a Y can be screened
  • Optional tests for microdeletions and other aneuploidies are also available

The verifi test was developed by, and its performance characteristics were determined by Verinata Health, Inc. a wholly owned subsidiary of Illumina, Inc. The VHI laboratory is CAP-accredited and certified under the Clinical Laboratory Improvement Amendments (CLIA) as qualified to perform high complexity clinical laboratory testing. It has not been cleared or approved by the U.S. Food and Drug Administration.

VeriSeq NIPT Analysis Software (16 Samples)

  • Easy-to-use, validated CE-IVD marked NIPT analysis software removes the burden of bioinformatics development
  • Proven, whole-genome sequencing (WGS)-based NIPT analysis method shown to minimize test failures1,2
  • Fast turnaround enables users to go from sequencing data to NIPT results in 2 hours on a secure, onsite server

Learn more about VeriSeq NIPT Analysis Software

1Data on file. Illumina, Inc. 2015.
2Taneja PA, Snyder HL, de Feo E, et al. Noninvasive prenatal testing in the general obstetric population: clinical performance and counseling considerations in over 85 000 cases. Prenat. Diagn. 2015;Dec 30. Doi: 10.1002/pd.4766. [Epub ahead of print].


  • What conditions does the verifi Prenatal Test screen for?

    The verifi test screens for trisomies 21, 18 and 13. There is an option for sex chromosomes Monosomy X, Triple X, XXY, XYY and fetal sex (XX or XY) and selected microdeletions as well.

  • How are results reported for the verifi Prenatal Test?

    Test reports will include one of three possible results for chromosomes 21, 18, and 13: “No Aneuploidy Detected”, “Aneuploidy Detected”, or “Aneuploidy Suspected (Borderline Value)”.

    • “No Aneuploidy Detected”—this result is reassuring but does not ensure an unaffected pregnancy.

    • “Aneuploidy Detected”—this result suggests an increased likelihood of the fetus to be affected. However, there is a small chance that the result may not reflect the chromosomes of the fetus.

    • “Aneuploidy Suspected (Borderline Value)”—this result gives an indication that although there is a higher risk for fetal aneuploidy than a “No Aneuploidy Detected” result, the chances of a false positive are slightly greater than the results in the “Aneuploidy Detected” zone. Both “ANEUPLOIDY SUSPECTED (Borderline Value)” and “ANEUPLOIDY DETECTED” results should be confirmed by an invasive procedure. Illumina recommends that no irreversible clinical decisions should be made based on these screening results alone. If definitive diagnosis is desired, chorionic villus sampling or amniocentesis would be necessary.

  • How are results reported for the sex chromosomes option?

    For singleton pregnancies sex chromosome results are reported in cases where requested. If there are no sex chromosome aneuploidies, then the report will indicate XX or XY status. It is for the provider and patient to decide if the fetal sex information is to be revealed to the patient.

Additional NIPT Resources

10× Higher Positive Predictive Value Read Article Study published in NEJM finds verifi Prenatal Test achieves 10×higher positive predictive value vs. current standard of care.

Integrating Noninvasive DNA Testing (NIDT) into the Prenatal Testing Paradigm View video Dr. Bianchi discusses current aneuploidy screening methods, NIDT, results from NIDT clinical trials, and the future of prenatal diagnosis.

An MFM's Perspective on NIPTDownload PDF Dr. Chavez discusses the benefits of NIPT for prenatal screening of fetal chromosomal aneuploidies.

Continuing Medical Education (CME)Learn MoreIllumina is committed to supporting independent medical education for women's healthcare providers. Click above to participate in a free CME activity about "The Role of Noninvasive Prenatal Screening in Optimizing Fetal Outcomes".

See all clinical lab resources

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