SeraSeq reference materials support non-invasive cfDNA screening methods.

BACKGROUND

Reference materials are essential for the validation, verification, and implementation of clinical assays. Seracare has developed the Seraseq line-commercial reference standards for non-invasive prenatal testing (NIPT)-which are designed to simulate maternal plasma containing cell-free DNA (cfDNA).

OBJECTIVE

This study aims to evaluate the performance of Seraseq reference materials compared to natural maternal plasma, particularly assessing their quality and reliability as reference standards in NIPT workflows, both with and without size selection to enrich fetal fraction.

METHODS

We analyzed six replicates from eight different Seraseq genotypes. cfDNA was extracted, prepared into sequencing libraries, and sequenced following the same protocols used for natural plasma samples. Size-selection was also applied to enrich shorter cfDNA fragments. The key performance metrics included cfDNA yield and integrity, library preparation efficiency, sequencing quality, fetal fraction estimation, and detection of aneuploidies and sex chromosome abnormalities.

RESULTS

cfDNA quantity and quality from Seraseq materials were comparable to natural plasma. The materials yielded consistent library concentrations. Sequencing showed reliable detection of all targeted aneuploidies except the microdeletion del22q11, even with elevated fetal fraction. Size-selection increased fetal fraction and improved Z-scores for aneuploidy detection across all genotypes. Fragment size profiles exhibited slight but consistent deviations from natural plasma, notably after size selection.

CONCLUSIONS

Seraseq reference materials closely mimic the cfDNA characteristics of maternal plasma and perform reliably across multiple testing dimensions. While they may present slight differences in fragment size periodicity, these did not affect analytical performance. These materials are therefore suitable for validating and monitoring NIPT workflows.