A-400 Development of a rapid point-of-care metabolic human blood panel for Na, K, Cl, and Ca diagnostics using the multimodal Fluxergy analyzer

Abstract

The development of rapid, accurate, and accessible point-of-care (POC) diagnostics is critical for improving clinical decision-making and patient outcomes. This study presents the development of a subset of sensors on the Fluxergy Analyzer that contributes to the Basic Metabolic Panel (BMP), focusing on quantitative measurements of key analytes, including sodium (Na+), potassium (K+), chloride (Cl-), and calcium (Ca++) in human blood. Reliable POC diagnostics depend on accurate measurements, therefore it is essential that the sensors remain reproducible and manufacturable at scale, while also maintaining competitive shelf life to ensure long-term stability in clinical settings. To meet these requirements, miniature microfluidic ion-selective electrodes (ISEs) sensors were formulated for single-use applications to selectively measure analyte concentrations in blood by detecting electrochemical potential differences while resisting bloodborne interferents. Sensor performance was evaluated using human plasma and blood samples then benchmarked against the Nova Biomedical Stat Profile Prime Plus (hereafter referred to as Nova), an FDA-cleared benchtop reference analyzer. Biosensing ISEs are calibrated then evaluated in human plasma and whole blood according to their measured analyte concentration versus the Nova measurement of the same sample, as well as their agreement with CLIA requirements. Multiple batches of sensors are tested in biological linearity samples spanning relevant human physiological concentration ranges to understand variability and ensure reliability for a wide range of users. Although these sensors should ideally be equal to or better than the Nova reference analyzer, specific potentiometric performance indicators such as signal noise, drift, and equilibration time can give more insight into the raw performance independent from comparative sensor evaluation. Optimization of the ISEs improved accuracy in the clinically relevant range. All analytes demonstrated strong linearity against the Nova reference analyzer, with most samples meeting CLIA accuracy limits (+/-4 mmol for Na?, +/-0.3 mmol for K?, +/-5% for Cl?, and +/-0.25 mmol for Ca+?). The results were consistent across multiple sensor lots, indicating a stable and reproducible manufacturing process with resistance to common interferents and biofouling. Because the system is designed for single-use operation, each sensor is calibrated and measured once then disposed of, minimizing signal drift and memory effects. The results support the feasibility of a miniature and scalable metabolic panel for measuring human blood ion concentrations, with Na+, K+, Cl-, and Ca++ sensors showing strong agreement with the reference analyzer. Further optimization and accelerated age stress-testing is required to ultimately achieve greater than 95% CLIA acceptance across the panel for the shelf life of the product. This enables low-cost POC diagnostics for rapid results in resource-limited clinical settings where expensive lab-scale unimodal analyzers are impractical.