Why NGS adapters and indexing primers matter

• Efficient multiplexing: Indexing primers introduce unique barcode sequences through i5 and i7 indexes, allowing multiple samples to be pooled and sequenced in a single run while maintaining sample identification throughout the workflow.
• Reliable library preparation: Sequencing adapters provide the functional elements required for library preparation, including flow cell binding sequences and sequencing primer binding sites that enable sequencing and data generation.
• Improved data quality: High-quality adapters and indexing primers can help reduce barcode crosstalk, index misassignment and contamination-related issues that may affect downstream analysis and interpretation.
• Flexible indexing options: Single-index, dual-index and unique dual index (UDI) configurations support a range of sequencing applications, from smaller research projects to large-scale multiplexed sequencing programmes.
• Scalable supply: Custom manufacturing options enable research organisations, sequencing facilities, diagnostics developers and kit manufacturers to source indexing primers and adapter sets tailored to their workflow and throughput requirements.

What do NGS adapters do in library preparation?

NGS adapters perform several essential functions during library preparation. They contain the sequences required for library fragments to bind to the sequencing flow cell, provide primer binding sites for sequencing reactions and support sample multiplexing through index incorporation. Together with indexing primers, adapters enable multiple samples to be pooled in a single sequencing run while maintaining accurate sample identification during downstream analysis.

Choosing an NGS indexing strategy

Different indexing approaches can affect sequencing accuracy, sample tracking and multiplexing capacity. Single-index strategies may be appropriate for smaller studies, while dual-index and unique dual index (UDI) approaches can help reduce the risk of sample misassignment in high-throughput sequencing workflows. Selecting the appropriate indexing strategy depends on application requirements, sample numbers and sequencing platform compatibility. Organisations developing large multiplexed sequencing programmes often adopt dual-index or UDI designs to strengthen sample identification and support data integrity.

Reducing barcode crosstalk and sample misassignment

Accurate sample identification is critical for multiplexed sequencing. Barcode crosstalk, index hopping and oligonucleotide contamination can contribute to sample misassignment and affect sequencing accuracy. High-purity oligonucleotides, dedicated manufacturing controls and routine monitoring processes help minimise these risks and support confidence in sequencing results.

Benefits of NxGrade™ NGS indexing primers and adapters

NxGrade™ NGS indexing primers and adapters are designed to support sequencing accuracy, workflow reproducibility and scalable sample multiplexing. Key benefits include:

• High-purity oligonucleotides through optimised RPC purification.
• Low cross-contamination levels supported by dedicated manufacturing workflows.
• Reduced barcode crosstalk risk in multiplexed sequencing applications.
• Flexible delivery options to support different workflow requirements.
• Comprehensive quality control with mass spectrometry and analytical UPLC testing.
• Scalable manufacturing support for research and commercial sequencing programmes.