Host interference is a major challenge in mNGS due to the much larger size of the host genome compared to microbial genomes.
The human genome is approximately 1,000×larger than bacterial genomes and 1,000,000×larger than viral ones. Even trace amounts of host nucleic acids can flood sequencing libraries, obscure microbial reads, and compromise taxonomic accuracy.
Various host depletion methods exist, but each has its limitations.
such as mechanical, chemical, or enzymatic approaches, add significant cost, time, and complexity to the workflow. They can also alter the microbial community composition, leading to inaccurate pathogen profiles.
like computational removal of host sequences, require deep coverage, which wastes valuable sequencing resources and increases costs.
Each method involves tradeoffs in terms of cost, speed, accuracy, and microbial community preservation.
* The majority of studies have focused on non-blood sample types; very few workflows have been validated directly on blood specimens.
For a detailed comparison of these techniques
ZISC is a zwitterionic membrane composed of a cross-linked polymer with alternating positive and negative charges. When sample material is pushed through the filter:
Nucleated cells such as leukocytes are a major source of host DNA in biological samples, and their capture on the ZISC membrane significantly reduces the amount of host DNA that carries over into downstream mNGS analysis.
Charge-mediated retention mechanisms may apply to a broader range of nucleated host cells beyond leukocytes, potentially contributing to a rebalancing of host-to-microbe nucleic acid ratios in diverse biological matrices.
The Devin Host Depletion filters have undergone rigorous tests validating its high nucleated cell retention and the microbial passing efficiency.
The white blood cell (WBC) depletion efficiency of the Devin filter with different blood volumes. The orange dotted line represents the detection limit of WBCs in cell culture.
Total colony forming units (CFUs)/mL of blood sample.
Devin Host Depletion filters have a fundamentally different operating principle than other methods. The results yield more microbial DNA thus improving mNGS results while reducing cost and complexity.
Devin filters improve microbial enrichment by up to 1,000×, reducing the required sequencing depth and consumables.
For clinical labs, time is often a limiting factor. Devin filters eliminate >99% of host material in under 2 minutes without additional reagents, chemicals, or incubation.
Removing even a small amount of host nucleic acid can drastically shift the signal-to-noise ratio. By removing host material prior to extraction, the Devin Filter enhances downstream microbial signal fidelity.
In validation studies:
Sepsis samples:
microbial reads increased from 46 to 243 RPM.
The filter preserves taxonomic structure—crucial for microbiome research—and improves pathogen detection in low biomass clinical samples.
Devin™ Host
Depletion Filter
The Devin filter is the first step in a purpose-built mNGS workflow.
Devin™ Microbial
DNA Enrichment Kit
mNGS-grade reagents to reduce contamination
Devin™ Automated Microbial DNA Enrichment Kit
Generate libraries from as low as 10 pg input
Devin™ Host
Depletion Filter
Curated, cloud-based or on-premise bioinformatics
The Devin filter is not a blood fractionation filter in the traditional sense — it does not separate whole blood into plasma, red cells, white cells, and platelets the way fractionation membranes designed for transfusion do. Devin is purpose-built for metagenomic sequencing: it removes mammalian nucleated cells (the dominant source of host DNA) via a charge-based capture mechanism while preserving microorganisms in the filtrate. If your goal is to enrich microbial DNA from whole blood for mNGS or PCR-based pathogen detection, Devin replaces the entire fractionation step. If your goal is to recover plasma or specific cell populations for hematology or transfusion applications, a conventional fractionation device is the right tool.
Traditional blood fractionation filters separate components by physical size or density — pore sizes and centrifugation forces are calibrated to retain or release specific cell populations. Host-depletion filtration with Devin works by a fundamentally different mechanism: a 15–20 µm membrane is coated with zwitterionic polymers (Zwitterionic Interface Self-assemble Coating, or ZISC) that bind the membrane proteins of mammalian nucleated cells. The pore size is deliberately larger than human cells — it is the surface chemistry, not the geometry, that provides selectivity. This has three practical consequences for mNGS workflows: (1) microorganisms pass through with greater than 90% efficiency, (2) the filter does not clog at clinically relevant blood volumes, and (3) no reagents, enzymes, or chemistry steps are required, eliminating reagent-borne contamination risk that affects DNase-based depletion methods.
Devin has been validated across a wide range of sample volumes:
Filtration completes in under five minutes regardless of input volume, and the workflow requires no reagents, enzymes, or chemical buffers — an important advantage when working with the smallest sample volumes where reagent-borne contamination would otherwise dominate the signal.
Use Devin host depletion when the workflow constraint is host-cell background before DNA extraction. The strongest fit is a host-rich sample where nucleated mammalian cells consume sequencing depth, slow extraction, or reduce pathogen sensitivity.
For a complete sample-to-report path, pair Devin filtration with the Devin Microbial DNA Enrichment Kit, Unison Ultralow DNA NGS Library Prep Kit, and PaRTI-Seq Analysis when those components fit the study or assay design.
The useful output is not simply less total DNA. The useful output is a higher usable microbial fraction with microbial composition preserved well enough for the intended interpretation.
High human read fraction after filtration: check whether the sample was stored long enough for host-cell lysis before filtration. Devin captures intact nucleated cells; it cannot remove host DNA that was already released into solution.
Low total DNA after filtration: this can be expected in low-biomass samples. The key question is whether microbial fraction improved, not whether total DNA stayed high. Route the filtrate into a low-input library preparation workflow when needed.
Microbial signal drops compared with unfiltered input: review sample loading, filter handling, and matrix compatibility. Include organism spike-ins or paired specimens where possible to separate true low microbial load from workflow loss.
Extraction automation struggles with the sample: check whether the pre-filter sample was viscous or cell-rich. Host depletion may improve downstream extraction handling by reducing host-cell burden, but clotting or sample debris can still disrupt automation.
Contamination controls show background organisms: host depletion does not remove reagent background introduced downstream. Use extraction blanks, lot-aware controls, and an mNGS-grade extraction workflow such as Devin Microbial DNA Enrichment when contamination control is the main bottleneck.
Filtered sample still fails sequencing QC: separate host-background failure from insufficient starting microbial DNA. If human reads are lower but microbial coverage is still inadequate, the next fix is likely specimen input, culture growth, extraction recovery, or library input.
Micronbrane Medical technologies enrich our understanding of microorganisms through innovative metagenomic collection devices, novel host depletion, mNGS-grade reagents, advanced metagenomic sequencing assays, automation instrumentation, plus rapid bioinformatic software.
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