NGS Sample Multiplexing Strategies to Reduce Costs

Reduce NGS costs effectively using advanced sample multiplexing techniques: barcoding, magnetic bead purification, miniaturization, and smart pooling. Ideal for high-throughput genomics, population st

Why Multiplexing Matters for Cost‑Effective NGS

Sample multiplexing tags each DNA fragment with a unique barcode (index) so that dozens to hundreds of libraries can be pooled and sequenced together. By sharing a single flow‑cell run, the fixed instrument and reagent costs are spread across many samples, driving the per‑sample sequencing expense down dramatically. Economic data show a steep decline in genome‑sequencing price: from $1 million in 2005 to <$200 today for a human genome, while high‑throughput platforms now generate >10 billion reads per run. This cost compression makes multiplexing essential – without it, the marginal cost of a shallow run would exceed that of a deep run, and the economies of scale offered by NovaSeq, Ultima UG100, or PacBio Revio would be lost. For Yaazh Xenomics and Indian research institutions, multiplexing enables affordable whole‑genome, exome, and targeted panels, supports large‑scale population studies, and aligns with national initiatives such as the Indian Genomics Initiative. By adopting dual‑index adapters, automated library prep, and high‑density pooling, Indian is can deliver fast, high‑precision data while keeping per‑sample budgets within reach.

Indexing Strategies – From Dual Indexes to UMIs

Key Points for Indexing Strategies

Result: Combined UDIs + UMIs + disciplined prep delivers reliable demultiplexing, uniform coverage, and cost savings.] Unique dual indexes (UDIs) are now the gold‑standard for multiplexed NGS runs because they attach a distinct i5 and i7 barcode to each library. By requiring both indexes to match during demultiplexing, UDIs dramatically reduce index hopping—misassignment of reads that can reach 1‑2 % and climb to 10 % with single‑index or ExAmp chemistries (Cytiva). The higher combinatorial space of UDIs also allows laboratories to pool hundreds of samples in a single lane, driving per‑sample reagent costs down. Molecular identifiers, or unique molecular identifiers (UMIs) add a short random sequence to each original DNA fragment before PCR. This barcode enables downstream software to collapse reads that originated from the same molecule, correcting PCR‑induced errors and eliminating duplicate‑read inflation. As a result, variant‑calling sensitivity improves and false‑positive rates fall, especially in low‑frequency applications such as tumor mutational burden or rare‑variant detection (Illumina, IDT). Best‑practice library preparation minimizes mis‑assignment: (1) use high‑fidelity polymerases and limit PCR cycles to preserve library complexity; (2) perform thorough bead‑based clean‑ups to remove free adapters that can cause index swapping; (3) quantify libraries accurately (Qubit or qPCR) and pool equimolarly; and (4) employ automation or platforms like ClickBio’s VBLOK200 to avoid pipette‑tip loss and ensure consistent library concentrations. When combined, UDIs, UMIs, and disciplined prep workflows deliver reliable demultiplexing, high coverage uniformity, and the cost savings essential for high‑throughput Indian labs such as Yaazh Xenomics.

Optimising Library Preparation – Beads, Enzymes, and Miniaturisation

![### Cost‑Saving Strategies for Library Prep

Impact: Maintains high‑fidelity and uniformity while dramatically lowering per‑sample expenses.] Cost‑efficient library preparation starts with magnetic‑bead‑based purification. Bead kits such as Sera‑Mag or home‑brew SPRI beads enable DNA extraction, size selection and clean‑up in a single, automatable step, eliminating column‑based consumables and reducing plastic waste. Because the beads capture nucleic acids with high recovery, they are especially useful for low‑input samples where loss is critical. A further savings lever is the use of third‑party consumables. Many laboratories replace vendor‑specific magnetic beads with lower‑priced equivalents or prepare home‑brew SPRI mixtures, achieving up to a 28‑fold cost reduction without compromising library quality. The next savings tier comes from scaling down reaction volumes and adopting 384‑well plate formats. Moving from 96‑well to 384‑well plate formats and adopting miniaturised library‑prep kits (e.g., Illumina Collibri or Thermo Fisher Mini‑Prep) cut reagent consumption by 50‑90 %. Smaller volumes also increase throughput, allowing hundreds of libraries to be processed in parallel on liquid‑handling robots. Combining bead‑based clean‑up, affordable third‑party reagents and 384‑well miniaturisation can lower per‑sample library‑prep expenses to well under $15, while maintaining the high‑fidelity and uniformity required for downstream multiplex sequencing.

Automation and Robotics – Cutting Hands‑On Time and Error

![### Automation Benefits

Hands‑On Time: Hours → Minutes Error Rate: Significantly reduced due to precise dispensing and air‑pocket detection. Result: Faster turn‑around, consistent library quality, lower labor and consumable waste. High‑throughput NGS labs such as Yaazh Xenomics can dramatically lower per‑sample expenses by replacing manual pipetting with liquid‑handling robots for library preparation, pooling, and normalization. The Myra pressure‑based dispensing system adds a safety net by detecting air pockets in wells, preventing drop‑outs during normalization and ensuring accurate equimolar pooling. These automated workflows reduce hands‑on time from hours to minutes, minimize human error, and enable consistent library quality across hundreds of samples per run. The throughput gains translate into long‑term labor cost savings: a single robot can process 384‑well plates in a fraction of the time a technician would need, freeing staff for data analysis and assay development. Moreover, low‑volume dispensing lowers consumable waste, supporting both cost‑effectiveness and sustainability goals in Indian laboratories. By integrating liquid‑handling robots, pressure‑based dispensers, and low‑volume technologies, labs achieve faster turn‑around, higher reproducibility, and a sustainable reduction in overall NGS workflow expenses.

Pooling Strategies – Equimolar vs. Targeted Coverage

Pooling Comparison

Key Takeaway: Accurate quantification is essential for both strategies; targeted pooling maximizes cost‑effectiveness while meeting specific coverage needs. Equimolar pooling is the simplest way to achieve a balanced read distribution across many libraries. By quantifying each library with a fluorometric assay such as Qubit or, more precisely, with qPCR that targets the adapter sequences, labs can calculate the exact femtomole amount to pool. Normalizing all libraries to the same molarity (e.g., 2 nM) ensures that each sample receives roughly the same number of reads, preventing over‑sequencing of some libraries and under‑sequencing of others. This approach is especially useful when all samples require the same coverage depth, such as in large population studies or uniform capture panels. Non‑equimolar (or targeted) pooling allows laboratories to allocate deeper coverage to a subset of high‑priority samples while keeping the overall pool size manageable. By adjusting the volume of each library according to its desired read depth, researchers can boost coverage for low‑input or clinically critical specimens without increasing the total number of sequencing lanes. Accurate quantification (qPCR or Qubit) remains essential, but the pooling calculator must incorporate the intended coverage ratios, often expressed as a proportion of total femtomoles (e.g., 3 µL for a high‑coverage sample versus 1 µL for routine samples). This strategy maximizes the cost‑effectiveness of a run while preserving the sensitivity needed for rare variant detection. Pre‑capture multiplexing pools indexed libraries before the hybrid‑capture step, reducing reagent consumption and simplifying the workflow. For example, Celemics has validated a 12‑plex pre‑capture protocol in which 300 ng of each library is combined into a single hybridization reaction. This early pooling yields uniform on‑target ratios comparable to single‑plex captures, lowers the amount of capture probe needed per sample, and shortens hands‑on time. The approach also mitigates library‑to‑library variation because the capture enzymes act on a mixed pool, leading to more consistent coverage across all samples. When combined with accurate equimolar or targeted pooling calculations, pre‑capture multiplexing becomes a powerful tool for high‑throughput, cost‑effective NGS projects.

Leveraging High‑Throughput Platforms and Third‑Party Vendors

Platform Cost Overview

Outsourcing: External sequencing and storage providers eliminate capital expenditure and maintenance costs, enabling Indian labs to focus on sample prep and analysis. Adopting ultra‑high‑throughput sequencers dramatically lowers per‑sample costs. Illumina’s NovaSeq X series can run up to 384‑plex pools, driving the cost of a human genome toward $200. Ultima Genomics’ UG 100 Solaris delivers >10 billion reads per run; its per‑genome price has already fallen to $80, a 20 % reduction from launch, and the platform’s high wafer output supports even larger multiplexes. PacBio Revio’s FiFi chemistry also accommodates 384‑sample SMRTbell index plates, sharing instrument capacity across many projects. Beyond hardware, many laboratories outsource sequencing and long‑term data storage to specialised service providers, eliminating capital outlays for sequencers, maintenance contracts, and on‑site storage infrastructure. This outsourcing model, combined with the falling cost curve—$200 per genome on NovaSeq X, $80 on Ultima UG 100 Solaris, and sub‑$100 on emerging platforms—creates a financially sustainable path for Indian genomics labs such as Yaazh Xenomics to offer affordable, high‑volume NGS services while maintaining data quality.

Sustainable Practices – Reducing Waste and Environmental Footprint

Sustainability Measures

Overall: Combining hardware thatm reagents and low‑volume automation aligns cost reduction with greener laboratory practices for Indian genomics facilities. Adopting low‑waste pooling technologies is a practical way for Indian laboratories such as Yaazh Xenomics to cut consumable costs while supporting sustainability goals. ClickBio’s VBLOK200 uses patented centrifugal collection to recover nearly 100 % of library volume from multi‑well plates, eliminating the need for repetitive pipette‑tip transfers that waste plastic tips and can cause library loss, especially for low‑abundance samples. This tip‑reduction approach aligns with the growing emphasis on greener lab practices in India. Complementary to hardware savings, Revvity’s NEXTFLEX product line offers cost‑effective cleanup beads and universal blockers. The NEXTFLEX NGS Cleanup Beads employ SPRI technology that achieves high recovery rates at up to 50 % lower cost than competing beads, while the universal blockers increase on‑target read numbers, reducing the amount of reagent required per run. Together, these innovations lower both plastic waste and reagent consumption, directly supporting Indian labs’ sustainability initiatives and helping them meet the nation’s broader environmental objectives without compromising data quality.

Putting It All Together – A Roadmap for Yaazh Xenomics

To keep per‑sample expenses low while maintaining data quality, Yaazh Xenomics should combine three proven cost‑saving pillars. First, integrate dual‑indexing (UDI) with magnetic bead‑based clean‑up and miniaturised reagent volumes. Unique dual indexes dramatically reduce index hopping, while bead‑based purification (e.g., SPRI or Sera‑Mag) streamlines size selection and can be automated in 384‑well plates, cutting consumable waste. Scaling down reaction volumes to half‑ or quarter‑size further lowers reagent spend without sacrificing library complexity. Second, adopt automation for library preparation and pooling. Liquid‑handling robots can dispense nanoliter volumes, reduce pipette‑tip usage, and perform early‑pooling steps such as VBLOK200 centrifugal collection, ensuring uniform library concentrations and minimizing human error. Finally, choose high‑output sequencers (Illumina NovaSeq X, Ultima UG100 Solaris, PacBio Revio) or outsource runs to specialised service providers. High‑throughput platforms amortise instrument and flow‑cell costs across hundreds of multiplexed samples, and outsourcing eliminates capital outlay and long‑term storage expenses. Together, these strategies enable Yaazh Xenomics to deliver fast, high‑precision NGS results at a fraction of the traditional cost.