Most claims about antibody performance come from the supplier making them. It is far rarer — and far more convincing — when an independent academic team puts a supplier's antibody pair through peer-reviewed clinical validation and publishes the result in a journal with no commercial stake in the outcome. That is exactly what happened in a study recently published in ACS Infectious Diseases by researchers at the Gwangju Institute of Science and Technology (GIST) and Chonnam National University Hospital in South Korea.1
The team built a new ultrasensitive influenza A rapid test platform called TELFIA (TMB-enhanced lateral flow immunoassay), and for its core antigen-capture chemistry they selected Sekbio's anti-influenza A nucleoprotein antibody pair, W37M and W36M. This article walks through what the researchers built, how they validated it against RT-PCR in clinical samples, and what the results tell IVD developers evaluating antibody suppliers for their own rapid test programs.
1. A New Benchmark for Influenza A Rapid Testing
A lateral flow immunoassay (LFIA) is a point-of-care diagnostic format in which a liquid sample migrates along a nitrocellulose membrane, allowing capture and detection antibodies to form a visible test line if the target antigen is present. LFIAs are the technology behind most rapid antigen tests, prized for delivering a result in minutes without laboratory equipment — but that convenience has historically come at the cost of sensitivity, since conventional LFIAs can miss low-viral-load samples that a lab-based RT-PCR test would catch.
The GIST team set out to close that sensitivity gap without sacrificing the format's simplicity. Their TELFIA platform reached a limit of detection (LoD) of 11.6 pg/mL for influenza A nucleoprotein within a 15-minute assay time — an approximately 1,000-fold improvement in sensitivity over conventional, unenhanced LFIA strips. In a clinical evaluation against real-time PCR across 126 measurements from 42 patient samples, the platform achieved 96.8% sensitivity and 98.4% specificity.
"An amplification chemistry is only as good as the antibody pair capturing the antigen in the first place — TELFIA's 1,000x sensitivity gain rests on a capture-detection pair that performs reliably under real clinical conditions."
2. Why the Antibody Pair Determines LFIA Sensitivity
An antibody pair in immunoassay development consists of a capture antibody, which immobilizes the target antigen on the membrane, and a detection antibody, which binds a separate, non-overlapping epitope on the same antigen to generate the visible signal. Choosing and validating this pair is widely regarded as the single most consequential decision in LFIA development — it is covered in depth in our guide to lateral flow assay antibody pair selection and our broader antibody pairing for sandwich immunoassays guide.
The reason is structural: no downstream chemistry can fix a poorly matched pair. If the capture and detection antibodies compete for the same epitope, cross-react with related respiratory viruses, or lose affinity after conjugation and storage, amplification technologies will intensify noise along with signal rather than improving true sensitivity. This is precisely why the GIST team's choice of antibody pair matters as much as the platinum nanoparticle chemistry they engineered around it.
Critical Principle
Signal amplification raises the ceiling on how much signal an assay can generate; it does nothing to raise the floor on specificity. A validated, high-affinity antibody pair is the prerequisite that determines whether amplification improves real diagnostic accuracy or simply produces a brighter, noisier test line.
3. Inside TELFIA: Platinum Nanoparticle Signal Amplification
TELFIA embeds its entire enhancement chemistry into a single predried cassette, so one sample drop both captures the target antigen and triggers on-strip signal amplification — no separate reagent-addition step required. Antibody-conjugated platinum nanoparticles (Pt NPs) captured at the test line catalyze the oxidation of TMB (3,3′,5,5′-tetramethylbenzidine), producing an intensely colored product that is read visually or, more precisely, by a companion smartphone application.
The improvement was measured directly against the same antibody pair running without enhancement:
| Detection Condition | Visual LoD (IAV Nucleoprotein) | Visual LoD (Virus Titer) |
|---|---|---|
| Without Pt NP Enhancement | 10,000 pg/mL | 200,000 TCID50/mL |
| With Pt NP Enhancement (TELFIA) | 100 pg/mL | 2,000 TCID50/mL |
| With Smartphone App Threshold | 11.6 pg/mL | — |
Smartphone-Based Readout
The TELFIA app captures a strip image, calculates a percentage/intensity ratio between the test line and background, and applies a machine-learning-derived threshold (ratio of 1.38, based on a third-degree polynomial regression with R² = 0.999) to automatically classify results as positive, negative, or invalid — removing subjective visual interpretation from the diagnostic decision.
4. The Sekbio Antibody Pair Behind the Study
The paper's Materials and Reagents section states plainly: "IAV detection (W37M) and capture (W36M) antibodies were purchased from SEKBIO (Shenzhen, China)."1 These two monoclonal antibodies, both targeting the influenza A nucleoprotein (NP) — the most abundant and highly conserved viral protein used for broad-spectrum influenza A detection — formed the antigen-capture core of every experiment in the study, from analytical sensitivity spiking through the full clinical cohort.
Sekbio's W36M capture antibody and W37M detection antibody correspond to the antibody pair behind our commercial Influenza A/B Antibody Pair, validated for both colloidal gold LFA and fluorescent FIA platform development. In the GIST study, the W37M detection antibody was additionally conjugated to 50 nm platinum nanoparticles, achieving a 76.97% conjugation efficiency — demonstrating that the antibody performs not only in standard rapid test formats, but also under the more demanding surface-adsorption chemistry required for nanoparticle-catalyzed signal amplification.
| Study Parameter | Result |
|---|---|
| Antibody Source | Sekbio (Shenzhen, China) — W37M (detection), W36M (capture) |
| Target Antigen | Influenza A virus nucleoprotein (NP) |
| Pt NP Conjugation Efficiency | 76.97% |
| Limit of Detection (LoD) | 11.6 pg/mL IAV NP |
| Assay Time | 15 minutes |
| Clinical Sensitivity / Specificity | 96.8% / 98.4% vs. RT-PCR |
5. Clinical Validation: Sensitivity, Specificity & Ct Correlation
Analytical sensitivity is only meaningful if it holds up in real patient specimens. The researchers tested 42 clinical samples (21 PCR-confirmed positive, 21 PCR-confirmed negative) in triplicate, yielding 126 total measurements collected at Chonnam National University Hospital under IRB approval (CNUHH-2023-054).
| Result | PCR Positive | PCR Negative |
|---|---|---|
| TELFIA Positive | 61 (true positive) | 1 (false positive) |
| TELFIA Negative | 2 (false negative) | 62 (true negative) |
From this confusion matrix, sensitivity was calculated at 96.8% (61/63) and specificity at 98.4% (62/63), both comfortably exceeding the FDA's minimum 80% sensitivity guideline for rapid influenza diagnostic tests. Beyond binary positive/negative classification, the platform also showed strong semiquantitative performance: percentage/intensity ratios correlated inversely with RT-PCR Ct values across the positive clinical samples, with a linear regression of Ct = −4.00 × ratio + 32.88 and R² = 0.832 — meaning the antibody-antigen signal tracked viral load closely enough to support semiquantitative estimates of infection burden, not just a yes/no call.
6. Eight-Week Stability Under Accelerated Aging
A rapid test antibody pair that performs well on day one but degrades in the supply chain is not commercially viable. To probe this, the researchers stored complete TELFIA cassettes at 37°C for 8 weeks under dark, controlled conditions — a standard accelerated-aging protocol used to project room-temperature shelf life — testing three negative controls and three 1 ng/mL positive samples weekly.
- Negative control ratios remained tightly clustered between 0.82 and 1.03 across all 8 weeks, with no upward drift indicating background degradation.
- Positive sample ratios (1 ng/mL IAV NP) stayed within 3.14–3.55 throughout the study period, showing no meaningful loss of signal intensity.
- Representative strip images captured at each weekly interval visually confirmed the numerical stability data, with no observable fading or background creep.
IVD Application Note
Stable performance under 8 weeks of 37°C accelerated aging indicates that both the Sekbio antibody-Pt NP conjugates and the predried TMB/H2O2/citric acid enhancing chemistry retained their catalytic and binding activity — a relevant data point for any manufacturer evaluating antibody pairs for commercial-scale, temperature-variable distribution.
7. What This Means for LFIA and FIA Developers
For IVD developers sourcing antibody pairs, independent, peer-reviewed clinical validation carries more weight than any datasheet claim, because it is generated by a team with no commercial interest in the antibody supplier's success. The GIST study provides exactly that kind of evidence for Sekbio's influenza A antibody pair:
- The pair performed reliably across a wide dynamic range, from picogram-level spiking studies to real nasopharyngeal clinical specimens.
- It tolerated conjugation to platinum nanoparticles for catalytic signal amplification, not just standard colloidal gold labeling.
- It met and exceeded FDA sensitivity benchmarks for rapid influenza diagnostics when paired with a well-engineered detection chemistry.
- It maintained consistent performance through 8 weeks of accelerated thermal stress testing.
Developers building next-generation amplified LFIA or FIA platforms — whether for influenza or other respiratory targets — can review the same Influenza A/B Antibody Pair used in this study, or work with our antibody development team on custom pairing and conjugation support for their specific assay format.
8. Frequently Asked Questions — Sekbio Antibodies in the TELFIA Study
What is the Sekbio antibody pair used in the TELFIA influenza A study?
The study used Sekbio's anti-influenza A nucleoprotein monoclonal antibodies W37M (detection antibody) and W36M (capture antibody), as documented in the Materials and Reagents section of the published paper. Both were sourced directly from Sekbio (Shenzhen, China) and used to build the TELFIA cassette's antigen-antibody sandwich.
What is a lateral flow immunoassay (LFIA)?
A lateral flow immunoassay (LFIA) is a point-of-care diagnostic format in which a liquid sample migrates along a nitrocellulose membrane, allowing capture and detection antibodies to form a visible test line if the target antigen is present. LFIAs are the technology behind most rapid antigen tests.
How much more sensitive is TELFIA than a conventional influenza rapid test?
TELFIA achieved a limit of detection of 11.6 pg/mL for influenza A nucleoprotein, roughly 1,000 times more sensitive than conventional unenhanced LFIA strips, which typically require nucleoprotein concentrations in the low micrograms-per-milliliter range for a visible positive result.
Can Sekbio's influenza A antibody pair be used with signal amplification chemistries like platinum nanoparticles?
Yes. In the GIST study, Sekbio's W37M antibody was conjugated to 50 nm platinum nanoparticles with a measured conjugation efficiency of 76.97%, confirming compatibility with catalytic nanoparticle labeling as well as standard colloidal gold and fluorescent conjugation used in commercial rapid test manufacturing.
How does TELFIA compare to RT-PCR for influenza A diagnosis?
Across 126 clinical measurements from 42 patient samples, TELFIA achieved 96.8% sensitivity and 98.4% specificity relative to real-time PCR, the diagnostic gold standard, while delivering results in 15 minutes at the point of care instead of the hours typically required for laboratory PCR testing.
Does Sekbio offer antibody pairs for other rapid respiratory diagnostics?
Yes. Beyond the influenza A/B antibody pair featured in this study, Sekbio supplies matched antibody pairs and antigens for H5N1 avian influenza, RSV, and other respiratory pathogens, all manufactured under ISO 13485 for LFA, FIA, and CLIA platforms. Visit our antibody development services page to discuss custom pairing and conjugation support.
9. Summary
- Third-party validation: Sekbio's W37M/W36M influenza A antibody pair was independently selected and validated by GIST and Chonnam National University Hospital researchers in a peer-reviewed ACS Infectious Diseases paper, with no commercial relationship influencing the results.
- Clinical-grade accuracy: The antibody pair supported 96.8% sensitivity and 98.4% specificity against RT-PCR across 126 clinical measurements.
- Compatible with advanced amplification: The detection antibody conjugated successfully to platinum nanoparticles at 76.97% efficiency, enabling a 1,000x sensitivity gain over conventional LFIA.
- Storage-stable: Performance remained consistent through 8 weeks of accelerated aging at 37°C, with no significant signal drift.
- Format-flexible: The same antibody pair underlying this study is available commercially for LFA and FIA rapid test development.
At Sekbio, we manufacture and supply monoclonal antibody pairs for influenza and other respiratory IVD targets under ISO 13485, with the analytical and clinical performance data to back them. If you're developing an amplified or conventional influenza rapid test and need a validated capture-detection pair, explore our Influenza A/B Antibody Pair or get in touch with our technical team.
References
- Choi, C. W.; Lee, K.; Park, H.; Lee, Y. E.; Shin, M. G.; Hong, D.; Kim, M.-G. A Single-Step Platinum Nanoparticle-Enhanced Lateral Flow Immunoassay Platform for Rapid Detection of Influenza A Virus. ACS Infectious Diseases. 2026. DOI: 10.1021/acsinfecdis.5c00731.