ReACT (Resilience Acute Challenge Test): Functional assessment of human adaptive capacity through controlled ex vivo challenge (ReACT)

Modern medicine offers a wide range of diagnostic tools to detect disease and estimate risk, yet it lacks a standardized method to measure an individual’s adaptive reserve, i.e. a systemic biological capacity that determines how the organism maintains stability when challenged. This adaptive reserve reflects the dynamic regulatory potential of the system, rather than the presence or absence of pathology. Despite its central role in health trajectories, it remains indirectly inferred rather than directly quantified. ReACT (Resilience Acute Challenge Test) is a functional ex vivo assay designed to quantify this intrinsic adaptive capacity. Using peripheral EDTA whole blood, aliquots are exposed for a defined period to graded concentrations of hydrogen peroxide (H2O2), generating a controlled oxidative challenge. LINE-1 methylation is quantified across doses and modelled as an individualized dose–response curve. From this parametric response, a Functional Adaptive Capacity Index is derived, capturing proportionality, stability, and deviation from calibrated reference geometry. The oxidative challenge serves as a calibrated biological probe to reveal intrinsic adaptive reserve. ReACT will be validated in two structured validation models, cyclic therapeutic regimens and physiological load cycles, selected for their reproducible challenge–recovery dynamics and measurable short-term endpoints. These models enable rigorous assessment of assay robustness, reproducibility, and functional coherence within the PoC timeframe. The project will deliver a standardized ex vivo protocol, reproducibility metrics, predefined performance thresholds, and a validated computational framework for index derivation, together with an intellectual property and preliminary regulatory positioning strategy. By converting adaptive reserve into a reproducible biological readout, ReACT advances the translational integration of adaptive capacity into defined decision-support contexts.