In this article, Biolegio highlights the critical role of NGS adapters and index primers in achieving accurate Minimal Residual Disease (MRD) results, where detecting extremely low levels of cancer DNA requires exceptional assay performance.

MRD testing is used to identify tiny traces of cancer that remain after treatment, often at levels as low as 0.01% of circulating DNA. In these highly sensitive applications, even minor contamination or sequencing errors can lead to false positives and potentially influence clinical decisions. While attention is often focused on sequencing platforms and bioinformatics, Biolegio argues that adapter and index primer quality is equally important.

The company emphasises three key requirements for reliable MRD assays:

• Ultra-low cross-contamination rates in co-synthesised Index & Adapter oligos below 0.01% to prevent sample misassignment and background noise. Verified by NGS QC on every production batch.
• Carefully designed 10-base Unique Dual Indexes (UDIs) that improve demultiplexing accuracy and reduce the risk of index hopping.
• Unique Molecular Identifiers (UMIs) that enable accurate detection of true variants while eliminating PCR-related errors and duplication bias.

To meet these standards, Biolegio has rebuilt its NGS oligo production workflow, introducing dedicated synthesis equipment, enhanced contamination-control procedures, automation, and a specialised NGS-based quality control platform capable of detecting contamination at frequencies relevant to MRD applications. The company validates every production batch using sequencing-based QC data to verify performance.

According to Biolegio, adapter quality should be regarded as a clinical variable rather than a routine consumable specification. By combining NGS-verified contamination control, optimised UDI design, and UMI-enabled workflows, laboratories can improve confidence in MRD results and support more reliable patient monitoring and treatment decisions.

Biolegio’s LegiSeq NGS Ready-to-Use Oligos are manufactured under ISO 13485 standards and are designed to provide the quality and traceability required for clinical and diagnostic NGS workflows.

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