Choosing the Right Lateral Flow Assay Development Partner: Reducing Risk from Design to Scale.

(4-5 minutes)

Lateral Flow Assays (LFAs) may look simple, but successful development is far from straightforward. Behind reliable, consistent performance lies careful control of multiple interacting variables that can otherwise introduce hidden risk.

Too often, development challenges surface late, when changes are costly, timelines slip and verification efforts fail. The difference between a smooth path to market and repeated re-design frequently comes down to early technical decisions and the expertise of the development partner guiding them.

Success often comes down to partnering with experts who anticipate technical and regulatory challenges and respond quickly as project needs evolve. The right partner does more than execute experiments they guide early design decisions, understand the clinical relevance of the assay and align development with regulatory expectations from the outset.

When evaluating a potential development partner, look for teams that can clearly explain how they make these early decisions and how regulatory considerations influence development from the start.

Why Early Decisions Make All the Difference

In lateral flow development, early technical choices have a long lasting impact. Factors like antibody selection, conjugation chemistry, membrane choice, buffer formulation and flow dynamics all interact. Mistakes embedded early are costly to reverse, while informed decisions prevent delays, re-design and downstream verification failures.

A strong partner helps translate assay requirements into a practical, optimised design, enabling resource efficient decision making from the outset. They embed robust project management into the process, ensuring clear communication across teams and integrate regulatory and quality considerations early. When selecting a partner, ask how intended use, usability and clinical relevance are defined and revisited throughout development.

Critical Reagent Design

Antibody choice is a critical factor in LFA performance. Plate based performance such as affinity alone doesn’t guarantee success on a lateral flow strip, making assay relevant antibody screening essential for compatibility and robust performance. An experienced lateral flow assay development partner will incorporate high throughput, assay relevant reagent screening into the development workflow enabling informed decisions early in development, before significant time and resources are committed. For this reason, a key question when evaluating a development partner is how antibody screening is performed and whether it reflects the actual lateral flow assay format.

Conjugation chemistry and particle selection also play a major role. The type of particle (gold, latex, or fluorescent), conjugation approach (covalent or passive) and loading or orientation directly impact signal intensity, stability, and reproducibility. Strong partners can explain how these choices are controlled and documented to ensure batch to batch consistency. Attention to these details at the design stage helps to ensure assays behave predictably as they move from prototype to scale up.

Optimising LFAs as a System

In LFAs antibodies, conjugates, buffers, membranes, and flow dynamics all interact, influencing sensitivity, specificity, reproducibility and read time. Even small changes can ripple through the system, affecting matrix compatibility, nonspecific binding and overall assay behaviour.

A system level approach where chemistry, assay engineering and design are coordinated helps detect interactions early, balance critical performance characteristics and adapt quickly as project needs evolve.

Testing variables in combination, such as paired antibody and buffer conditions, reveals interactions that single component experiments may miss, allowing rapid iteration to optimise assay performance without delaying timelines. This coordinated approach ensures assays are optimised as a whole, not just as a collection of parts, reducing late stage surprises. Partners who optimise at a system level rather than component by component are better positioned to identify and manage these interactions.

Development Under ISO 13485: More Than Documentation

For IVD assays, working under ISO 13485 is more than documentation; a structured design control framework supports right first time development through deliberate, traceable decision making. Regular project reviews within this framework keep teams aligned, while regulatory considerations run alongside technical design, ensuring traceable decisions and early alignment with FDA 510(k) and EU IVDR requirements, supporting smoother submissions.

Design inputs, including intended use and performance targets, guide optimisation based on both technical goals and real world requirements. ISO 14971 aligned risk management informs hazard identification, risk evaluation and risk controls that prioritise inherent safety by design. When selecting a development partner, ask how ISO 13485 design controls and risk management are applied during early optimisation.

Regulatory Ready Performance Verification

Verification shouldn’t be an afterthought. While performance checks during development help guide optimisation, formal verification confirms the assay meets its intended analytical performance under defined conditions.

When selecting a development partner, it is important to ensure they follow a robust verification process that supports regulatory claims, including CE marking and FDA submissions. Verification reports provide objective evidence that the assay meets requirements such as limit of detection (LoD), linearity, precision, accuracy, specificity, and stability.

Data generated through rigorous verification should be traceable and technically robust, providing confidence not only for regulatory submissions but also for successful transfer to manufacturing. Choosing a partner who emphasizes thorough performance verification provides confidence in both regulatory readiness and manufacturing transfer.

Designing for Scale, Transfer and Use

Bench scale success is only the beginning. An assay that works well in the lab can struggle during pilot runs if scale, lot to lot variability or workflow integration aren’t considered. Early design decisions directly influence manufacturing yield, cost of goods, and real world performance.

By building in reagent consistency, process tolerances, and transfer ready protocols, assays can move smoothly from bench to production. This early planning reduces downstream risk and results in robust, reproducible and user ready assays. When evaluating a partner, ask how scale up and transfer considerations are addressed during development rather than after optimisation is complete.

The Right Partner Makes All the Difference

The best LFA development partners combine:

• Regulatory confidence and risk informed design built into every decision, supporting

FDA 510(k) and EU IVDR submission readiness.

• Deep technical expertise and hands on lateral flow experience.

• Rigorous ISO 13485 quality system practices that support right first time development

• Early consideration of usability, manufacturability and integration into real world workflows.

• Integrated project management that keeps milestones, decisions and feedback aligned while remaining agile to changing priorities or emerging insights

Together, these factors determine whether an assay stalls in development or reaches the market with confidence. Used as evaluation criteria, these capabilities help organisations identify partners who can reduce risk from design through scale. Whether launching a new LFA program or troubleshooting an existing one, engaging the right lateral flow assay development partner early reduces risk, protects timelines and accelerates time to launch.

If you are planning a new LFA program or addressing challenges with an existing one, Fleet Bioprocessing Ltd. can provide guidance and support. Learn more about our LFA development services or contact us to discuss your project.

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