Non-invasive prenatal chromosomal aneuploidy testing--clinical experience: 100,000 clinical samples.

OBJECTIVE: As the first laboratory to offer massively parallel sequencing-based noninvasive prenatal testing (NIPT) for fetal aneuploidies, Sequenom Laboratories has been able to collect the largest clinical population experience data to date, including >100,000 clinical samples from all 50 U.S. states and 13 other countries. The objective of this study is to give a robust clinical picture of the current laboratory performance of the MaterniT21 PLUS LDT. STUDY DESIGN: The study includes plasma samples collected from patients with high-risk pregnancies in our CLIA-licensed, CAP-accredited laboratory between August 2012 to June 2013. Samples were assessed for trisomies 13, 18, 21 and for the presence of chromosome Y-specific DNA. Sample data and ad hoc outcome information provided by the clinician was compiled and reviewed to determine the characteristics of this patient population, as well as estimate the assay performance in a clinical setting. RESULTS: NIPT patients most commonly undergo testing at an average of 15 weeks, 3 days gestation; and average 35.1 years of age. The average turnaround time is 4.54 business days and an overall 1.3% not reportable rate. The positivity rate for Trisomy 21 was 1.51%, followed by 0.45% and 0.21% rate for Trisomies 18 and 13, respectively. NIPT positivity rates are similar to previous large clinical studies of aneuploidy in women of maternal age ≥ 35 undergoing amniocentesis. In this population 3519 patients had multifetal gestations (3.5%) with 2.61% yielding a positive NIPT result. CONCLUSION: NIPT has been commercially offered for just over 2 years and the clinical use by patients and clinicians has increased significantly. The risks associated with invasive testing have been substantially reduced by providing another assessment of aneuploidy status in high-risk patients. The accuracy and NIPT assay positivity rate are as predicted by clinical validations and the test demonstrates improvement in the current standard of care

Breakdown of the NIPT Final Results.

<p>Trisomy 13 and 18 began reporting in February 2012.</p><p>Breakdown of the NIPT Final Results.</p

NIPT T21 Modeled Performance at Low Fetal Fractions.

<p>In figure, 27,824 samples that passed all laboratory quality criteria with fetal fractions between 4 and 8% were fitted into two normal distributions, one for euploids and one for T21 positives. The fitted distribution was used to estimate specificity and sensitivity.</p

NIPT Laboratory Performance.

<p>The table shows key laboratory performance indicators. Business days are defined as Monday through Friday excluding federal holidays. Canceled tests are samples that are inappropriate for testing primarily those with no indication for testing. Amended reports primarily include reports amended for typographical errors.</p><p>NIPT Laboratory Performance.</p

Impact of BMI on Final Results.

<p>This figure shows a breakdown of final results when binned by maternal BMI. The number of patients in each bin is displayed above their respective bin.</p

Average NIPT Patient Demographics (n = 100,000).

<p>Gestational age was determined by LMP or ultrasound. Maternal height and weight are not required for testing and not provided for all samples, n = 86,734.</p><p>Average NIPT Patient Demographics (n = 100,000).</p

Performance of a Multianalyte ‘Rule-Out’ Assay in Pregnant Individuals With Suspected Preeclampsia

Background: The ability to diagnose preeclampsia clinically is suboptimal. Our objective was to validate a novel multianalyte assay and characterize its performance, when intended for use as an aid to rule-out preeclampsia. Methods: Prospective, multicenter cohort study of pregnant individuals presenting between 28 0/7 and 36 6/7 weeks’ with preeclampsia-associated signs and symptoms. Individuals not diagnosed with preeclampsia after baseline evaluation were enrolled in the study cohort, with those who later developed preeclampsia, classified as cases and compared with a negative control group who did not develop preeclampsia. Individuals with assay values at time of enrollment ≥0.0325, determined using a previously developed algorithm, considered at risk. The primary analysis was the time to develop preeclampsia assessed using a multivariate Cox regression model. Results: One thousand thirty-six pregnant individuals were enrolled in the study cohort with an incidence of preeclampsia of 30.3% (27.6%–33.2%). The time to develop preeclampsia was shorter for those with an at-risk compared with negative assay result (log-rank P <0.0001; adjusted hazard ratio of 4.81 [3.69–6.27, P <0.0001]). The performance metrics for the assay to rule-out preeclampsia within 7 days of enrollment showed a sensitivity 76.4% (67.5%–83.5%), negative predictive value 95.0% (92.8%–96.6%), and negative likelihood ratio 0.46 (0.32–0.65). Assay performance improved if delivery occurred <37 weeks and for individuals enrolled between 28 and 35 weeks. Conclusions: We confirmed that a novel multianalyte assay was associated with the time to develop preeclampsia and has a moderate sensitivity and negative likelihood ratio but high negative predictive value when assessed as an aid to rule out preeclampsia within 7 days of enrollment. Registration: The study was registered on Clinicaltrials.gov (Identifier NCT02780414)