Tag: digital pcr

Why do Influenza A and B in wastewater matter?

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Community-level surveillance

Studies have demonstrated that Influenza A RNA is reliably detectable in wastewater, while Influenza B is detectable but generally at lower concentrations. For example:

  • A study of 100 samples from wastewater treatment plants in Karnataka, India found 18% positive for influenza A and 2% for influenza B, with detectable loads. (Panneerselvam, et al.)
  • Another investigation demonstrated that concentrations of influenza A and B in wastewater followed trends observed in clinical laboratory data. (Boehm, et al.)

Thus, wastewater viral signals can serve as a leading indicator of influenza circulation, potentially giving public‐health authorities earlier warning of rising activity.

Integration of human and animal/zoonotic signals (One Health)

Influenza A viruses have zoonotic potential. For instance, the highly pathogenic avian influenza (HPAI) A(H5N1) outbreak among dairy cattle and poultry in the U.S. prompted wastewater surveillance; detection of H5 subtype RNA in wastewater aligned with animal outbreaks (Louis, et al.).

Wastewater signals thus might capture inputs from human excretion and from animal sources (via animal waste, farm runoff, milk processing, wild birds). This provides a broader view of influenza virus ecology and spill‐over risk.

Early‐warning and preparedness

Wastewater integrates signals from symptomatic, asymptomatic, and untested individuals, providing a more complete picture of population-level infection, therefore WBE can provide advance notice of rising transmission or unusual viral activity (e.g., a novel strain, bovine/poultry spill-over). For example, one study reported a 17-day lead time in forecasting a city‐wide outbreak of influenza via wastewater subtyping (Mercier, et al.).

Such lead time can support public-health stakeholders to ramp up diagnostics, vaccination campaigns, and communicate risks.

What are the implications of wastewater surveillance for Influenza A & B?

Vaccine and resource planning

Early signals of rising influenza viral load in wastewater can inform decisions on vaccination campaigns (timing, scale), hospital readiness (stockpiling antivirals, ICU capacity), and public messaging (e.g., encouraging immunization, hygiene).

Research and emerging pathogens

Although sequencing influenza from wastewater remains technically challenging, improving workflows may enable earlier detection of new variants and reassortments before they are widely identified in clinical settings (Mercier, et al.).

Tools like the GT Molecular GT‑Fast Prep Influenza A Library Kit for Illumina® are accelerating this progress by enabling targeted amplicon sequencing of the most important circulating subtypes (H1N1 and H3N2). By providing more sensitive and subtype‑specific genomic data directly from wastewater, these kits help generate actionable insights on flu variant dynamics and further bridge the gap between environmental surveillance and real‑time public health decision‑making.

A new frontier in public health

Although influenza tends to appear at lower concentrations in wastewater than enteric viruses, consistent detection across systems demonstrates that wastewater-based epidemiology is effective for community-level disease tracking.

Wastewater surveillance is proving that the pipes beneath our cities aren’t just carrying away waste, they’re carrying valuable health information. With continued research and integration into public health systems, keeping an eye on our sewers could soon become one of the smartest ways to stay ahead of the flu.

GT Molecular provides digital PCR assays optimized for wastewater matrices, including panels targeting Influenza A and B. These tools support routine surveillance, outbreak detection, and monitoring to help communities stay ahead of seasonal and emerging influenza activity.

GT Molecular provides digital PCR assays optimized for wastewater matrices, including panels targeting Influenza A and B.  The GT Molecular Influenza A NGS Library Prep Kit provides further insights into circulating subtypes. These tools support routine surveillance, outbreak detection, and monitoring to help communities stay ahead of seasonal and emerging influenza activity.

ESR1 testing with digital PCR: A powerful tool for precision oncology

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Why do ESR1 mutations matter?

The ESR1 gene encodes estrogen receptor alpha (ERα), a transcription factor that drives tumor growth in ER+ disease. Acquired mutations in ESR1—especially in the ligand-binding domain such as Y537S, Y537N, Y537C, and D538G—can lock the receptor in an active state even in the absence of estrogen. These mutations have been linked to resistance to aromatase inhibitors and can influence choices of alternative therapies. Because ESR1 mutations often evolve under treatment pressure, their timely, accurate detection is crucial.

The case for liquid biopsy

Traditional tissue biopsies can be invasive and may not capture the full genomic diversity of metastatic disease. Liquid biopsy using circulating tumor DNA (ctDNA) offers a minimally invasive alternative that enables longitudinal monitoring. However, ctDNA often circulates at very low levels (as low as ~0.1% mutant allele fraction), which places high demands on the analytical sensitivity of testing methods.

Digital PCR vs. Next-Generation Sequencing for ESR1 testing

Digital PCR (dPCR)

Digital PCR partitions DNA into thousands of individual reactions and scores each for the presence or absence of target sequences. This approach allows absolute quantification without standard curves and pushes analytical sensitivity to very low variant allele frequencies (VAFs).

Key strengths of dPCR for ESR1 testing:

  • High sensitivity for known mutations: dPCR routinely detects ESR1 hotspot mutations at allele frequencies below 1%, even down toward ~0.1% or lower in well-optimized assays. (Raei, et al.)
  • Absolute quantification: Provides precise counts of mutant and wild-type alleles without standard curves.
  • Fast turnaround and simpler data: No complex bioinformatics required compared to sequencing.
  • Ideal for monitoring over time: Accurate, quantitative tracking of a known mutation burden as disease evolves.

Limitations:

  • Detects predetermined targets only—you must know which mutations you’re looking for in advance. dPCR is not designed for discovery of novel mutations outside the assay’s scope. (ESRI Biomarker testing, Eli Lilly)
  • Limited multiplexing compared with NGS (though newer panels like GT Molecular’s can multiplex several targets in one well). (GT Molecular ESR1 Panels)

Next-Generation Sequencing (NGS)

NGS provides a high-throughput approach that reads many DNA fragments in parallel, enabling comprehensive profiling of multiple genes and variants in a single run.

Key strengths of NGS for ESR1 testing:

Limitations:

  • Lower sensitivity at very low allele frequencies: Meta-analyses show that dPCR often outperforms NGS in sensitivity for detecting low-frequency ESR1 mutations in ctDNA. For example, sensitivity for dPCR in some studies was ~81% vs. ~57% for NGS. (Raei, et al.)
  • Longer turnaround and complex analysis: Sequencing workflows and bioinformatics can extend result times and require specialized expertise.
  • Potential higher cost per run: Especially when deep coverage is needed for low VAF detection.

When to use which method

In practical terms, many laboratories use both technologies in a complementary framework:

  • Use NGS initially to broadly profile tumors (including ESR1 and other genes), especially if unknown variants might be relevant.
  • Use dPCR for follow-up monitoring of known ESR1 mutations over time or in liquid biopsy when very small amounts of mutant DNA are expected. (Adorisio, et al.)

This integrated approach ensures both discovery power and sensitive longitudinal monitoring.

Why is Digital PCR a go-to tool for ESR1 testing?

Digital PCR’s combination of high analytical sensitivity, absolute quantification, and robust performance in liquid biopsy samples makes it an excellent choice for ESR1 mutation detection. It enables clinicians and researchers to:

  • Detect clinically important ESR1 mutations before radiographic progression
  • Track changes in mutation burden during therapy
  • Inform timely decisions about switching endocrine therapy or enrolling patients in clinical trials

By complementing broad sequencing efforts with focused, high-sensitivity testing, dPCR enhances molecular insight into treatment resistance.

GT Molecular’s dPCR ESR1 Testing Kit

For laboratories and research groups looking for a high-performance digital PCR solution for ESR1 mutation analysis, the GT-Plex™ ESR1 Mutation Panel from GT Molecular offers a powerful option. This multiplexed dPCR kit detects nine common ESR1 hotspot mutations plus wild-type ESR1 in a single well, enabling sensitive and specific quantification even in low-yield ctDNA samples. Designed for compatibility with widely used dPCR platforms, the kit includes all primers, probes, and controls to streamline workflows and support robust research results. (GT Molecular ESR1 Panel)

Whether you’re monitoring endocrine resistance during therapy or conducting preclinical research on breast cancer evolution, GT Molecular’s dPCR ESR1 testing kit provides a practical, high-sensitivity tool to deepen your molecular insights.

Whether you’re monitoring endocrine resistance during therapy or conducting preclinical research on breast cancer evolution, GT Molecular’s dPCR ESR1 testing kit provides a practical, high-sensitivity tool to deepen your molecular insights.