GenetiSure Dx Postnatal Assay Clinical Studies

The GenetiSure Dx Postnatal Assay has been validated and tested extensively. Below is a summary of the studies performed on the assay.

• Accuracy Study+

  • The analytical-accuracy study demonstrated the accuracy of the GenetiSure Dx Postnatal Assay using a panel of approximately 600 samples from different sources that exhibited aberrations across the entire genome. The average confirmation rates were 93.5% for larger CNVs (>20 probes) and 92.5% for small CNVs (5 to 20 probes). For cnLOH intervals, the average confirmation rate was 90.1%. The confirmation rate (%) is the number of assay-identified aberrations confirmed using a reference method divided by the total number of the assay-identified aberrations.

• Clinical Validity Study+

  • The GenetiSure Dx Postnatal Assay, which included 900 samples, was validated in a clinical study involving several partner laboratories. The study demonstrated that the assay has clinical validity and diagnostic utility, as compared to standard-of-care methods. The diagnostic yield for the assay, when considering only CNVs, was 15%, which was comparable to the diagnostic yield obtained for the same samples at the collection sites using non-Agilent microarray methods. This yield increased to 20% when cnLOH aberrations were also considered, exceeding the diagnostic yield at the collection sites.

• Limit of Detection Study+

  • To determine the analytical sensitivity, or Limit of Detection (LOD), of the GenetiSure Dx Postnatal Assay, a study was conducted to evaluate the minimum and maximum amounts of DNA acceptable as the assay input. Results support the use of 500 ng as the recommended input amount. The data demonstrated that performance did not decline down to 375 ng. For CNVs only, the LOD could be further reduced to 250 ng.

• Reproducibility Study+

  • The results of this study demonstrated that the GenetiSure Dx Postnatal Assay was reproducible when performed at multiple laboratory sites by different operators over multiple days and is suitable for implementation in a clinical laboratory environment.

• Precision Study+

  • The results of the precision study demonstrated that assay results are not affected by multiple extractions of the same sample, multiple reagent lots or scanners.

• Cross-Contamination Study+

  • The presence of contamination could result in corrupt and inaccurate patient data. This study was designed to determine whether cross contamination occurs during the routine assay workflow, and if so, what the impact on data would be. No suspected cross contamination was detected.

• Whole Blood Stability Study+

  • Whole blood specimens from the collection site may be stored prior to processing, or they may need to be transferred to a remote laboratory for processing; therefore, a whole blood stability study was performed. Whole blood specimens stored for up to 10 days at 2°C to 8°C prior to gDNA isolation, and then processed with the GenetiSure Dx Postnatal Assay, produced acceptable results.

• Interfering substances Study+

  • The GenetiSure Dx Postnatal Assay uses gDNA isolated from patient whole blood. Specimens may be obtained from patients with endogenous conditions resulting in hemolysis, bilirubinemia or lipemia. An interfering study was performed to determine the effects of these conditions on the results of the test. The study demonstrated that the assay results are not altered by the presence of excessive hemoglobin, triglycerides (triolein) or bilirubin (conjugated or unconjugated) in the patient whole blood specimen.

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