Characterization of commercially available cfDNA reference standards with the PGDx elio® plasma focus™ Dx

February 16, 2026

Key takeaways:

Verification studies require clinical plasma samples from cancer patients, but samples containing cfDNA are often difficult to obtain in large enough quantities for repeated testing, training, or troubleshooting
Cell line-derived reference materials can supplement verification studies to cover a wider range of variant allele frequencies (VAFs) and variant types
To provide reference data for PGDx elio plasma focus Dx verification studies, PGDx elio plasma focus Dx was performed by the PGDx laboratory, certified under the Clinical Laboratory Improvement Amendments (CLIA), according to the manufacturer’s instructions on reference materials from four vendors: Horizon Discovery Ltd. (Cambridge, UK), Thermo Fisher Scientific Inc. (Waltham, US), SeraCare Life Sciences, Inc. (Milford, US), and Twist Bioscience Corporation (South San Francisco, US)
To support robust verification, a diverse set of reference standards representing all assay-specific variant types, a range of VAFs, and different vendors is required. Twist cfDNA Ref Std, 5% VAF had the most variants overall in these studies, but SeraCare’s complete reference material and mutation mix at ≥2% VAF provided the greatest coverage of different variant types
Leveraging these materials supports broader adoption of PGDx elio plasma focus Dx and provides reproducible, clinically relevant results across laboratory settings

Madison J. Kelly, Kenneth C. Valkenburg, Jordan Woodrick, Kai Pollard, Efren Ballesteros, Jennifer Jackson, Aanavi Karandikar