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The Verifi Prenatal Test is highly accurate

A Genomic Solution for Noninvasive Prenatal Screening

NIPT (noninvasive prenatal testing) sensitivity and specificity are important considerations in choosing a test. The Verifi Prenatal Test is a highly accurate, noninvasive test that screens for aneuploidy of chromosomes 21, 18, and 13. Additional screening is available for sex chromosome aneuploidies, select microdeletions, and all autosomal trisomies in singleton pregnancies.

In twin pregnancies, screening for aneuploidy in chromosomes 21, 18, and 13 and the option to screen for the absence of the Y chromosome is available. Results are reported approximately 3–5 days after the sample is received. Depending on demand, the time to report may vary. Test performance metrics, including NIPT sensitivity, positive predictive values (PPV), and specificity data, are detailed below.


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Publication: 85,000 NIPT Cases

Noninvasive prenatal testing in the general obstetric population: Clinical performance and counseling considerations in over 85,000 cases.
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Test Performance Metrics for the Verifi Prenatal Test

The improved Verifi Prenatal Test has performance metrics that are equivalent to those of the original Verifi Prenatal Test.
Sensitivity and specificity for aneuploidy detected samples compared with published validation metrics
CLIA Laboratory Validation Study*
Condition Observed Sensitivity (Range) Observed Specificity (Range) Sensitivity Specificity
Trisomy 21 99.49% (98.66–99.53%) 99.77% (98.92–99.91%) 100% 99.76%
Trisomy 18 97.23% (94.20–98.15%) 99.69% (99.51–99.85%) 97.37% 99.57%
Trisomy 13 97.98% (95.56–98.87%) 99.84% (99.77-99.93%) 87.50% 100%

* 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.

† Observed sensitivity and specificities were calculated using available outcome data with the cohort size adjusted for the proportion of positive cases with confirmed outcomes.

‡ The low end of the range was based on the assumption that all unreported outcomes are discordant, and high end of the range was based on the assumption that all unreported outcomes are concordant.

Performance Metrics Considerations After Screening

PPV based on performance metrics

Positive predictive value (PPV) refers to the proportion of positive test results that are truly positive. PPV is based on the sensitivity and specificity of the test and the prevalence of the condition in the population being tested. Because the prevalence of autosomal trisomies (eg trisomy 21) increases with maternal age, so do the PPVs.

The American College of Medical Genetics (ACMG) recommends that laboratories provide patient-specific PPV when reporting positive results.1 Our test reports provide this information.

For Verifi and Verifi Plus Prenatal Tests, if a woman receives an aneuploidy detected result for trisomy 21, trisomy 18, or trisomy 13 in a singleton pregnancy, the report will include a PPV based on the test’s sensitivity and specificity for the condition, maternal age, and gestational age.

Sample Test Report
Chromosome Results PPV (%)
Chromosome 21 POSITIVE: Aneuploidy detected
Results consistent with pregnancy at increased risk for trisomy 21.
Chromosome 18 NEGATIVE: No aneuploidy detected
Results consistent with two copies of chromosome 18.
Chromosome 13 NEGATIVE: No aneuploidy detected
Results consistent with two copies of chromosome 13.

While PPVs are lower in younger women, PPVs for NIPT will be higher than those of traditional serum screening at all maternal ages because NIPT has significantly higher specificity (a lower false positive rate).2

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Why Prevalence Matters for PPVs

Because the prevalence of autosomal trisomies (eg, trisomy 21) increases with maternal age, so do the PPVs. Trisomy 21 is the most prevalent autosomal trisomy in live births. Thus, the PPVs are higher for trisomy 21 than for trisomies 18 and 13, which are less common.

The PPVs below are calculated based on age-related prevalence; the presence of other aneuploidy risk factors (eg, ultrasound abnormalities) would likely increase the PPVs over those shown here.

ppv prevalence graph
ppv specificity graph

Assessing Test Failure Rate

The Verifi Prenatal Test has the lowest published failure rate in the industry of 0.1%,3-5 excluding administered failed samples—that means that 99.9% of the time a result is provided.4 It uses next-generation sequencing to analyze cfDNA fragments across the whole genome, which has proven advantages over other NIPT methodologies such as targeted sequencing and array-based methods. Test failure rates are substantially lower with whole-genome sequencing versus other methodologies.4-7

That’s important, and clinically relevant, because not only do test failures negatively impact patient care, they also adversely affect test metric parameters such as sensitivity, specificity, and PPV. By choosing the Verifi Prenatal Test, the clinical impact of failures can be reduced.4

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verifi Prenatal Test Infographic

The Illumina Difference

We’re committed to providing laboratories with comprehensive solutions and test options to improve human health. Published data shows that NGS with whole-genome sequencing (WGS) is the NIPT technology of choice when compared to targeted approaches.

With over 99.7% of NIPT samples in these studies run on Illumina NGS technology, we’re helping advance breakthroughs in prenatal screening.

Click on the below to view the samples run data table.

99.7% of NIPT Samples in Published Studies Were Run on Illumina NGS Systems (2011-2017)
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  1. Gregg AR, Skotko BG, Benkendorf JL, et al. Noninvasive prenatal screening for fetal aneuploidy, 2016 update: a position statement of the American College of Medical Genetics and Genomics. Genet Med. 2016;18(10):1056-1065.
  2. Bianchi DW, Parker RL, Wentworth J, et al. DNA sequencing versus standard prenatal aneuploidy screening. N Engl J Med. 2014;370(9):799-808.
  3. Ryan A, Hunkapiller N, Banjevic M, et al. Validation of an enhanced version of a single-nucleotide polymorphism-based noninvasive prenatal test for detection of fetal aneuploidies. Fetal Diagn Ther. 2016;40(3):219-223.
  4. Taneja 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. 2016;36(3):237-243.
  5. McCullough RM, Almasri EA, Guan X, et al. Non-invasive prenatal chromosomal aneuploidy testing--clinical experience: 100,000 clinical samples. PLoS One. 2014;9(10):e109173.
  6. Norton ME, Jacobsson B, Swamy GK, et al. Cell-free DNA analysis for noninvasive examination of trisomy. N Engl J Med. 2015: 372(17): 1589-97.
  7. Dar P, Curnow KJ, Gross SJ, et al. Clinical experience and follow-up with large scale single-nucleotide polymorphism-based noninvasive prenatal aneuploidy testing. Am J Obstet Gynecol. 2014: 211(5): 527.e1-527.e17.
  8. 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.
  9. Nicolaides KH. Screening for fetal aneuploidies at 11 to 13 weeks. Prenat Diagn. 2011;31(1):7-15.
  10. Wald NJ, Rodeck C, Hackshaw AK, et al. SURUSS in perspective. Semin Perinatol. 2005;29(4):225-235.

The Verifi Prenatal 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.