Distance-based lateral flow immunoassay for quantitative detection of C-reactive protein in cardiovascular risk assessment

Abstract

C-reactive protein (CRP) is a key biomarker of inflammation, widely utilized for predicting cardiovascular disease (CVD) risk. Conventional detection methods often require sophisticated equipment and skilled personnel, limiting their accessibility in point-of-care testing (POCT). This study presents a novel distance-based lateral flow immunoassay (Dist-LFIA) for semi-quantitative CRP detection, offering a simple, portable, and cost-effective alternative. The device visually categorizes CRP levels into risk groups—low (<1 mg/L), intermediate (1–3 mg/L), and high (4–10 mg/L)—based on the length of a colorimetric signal, enabling easy interpretation without the need for advanced instrumentation. The Dist-LFIA demonstrated excellent analytical performance, achieving a detection limit of 0.12 mg/L, comparable recovery rates to immunoturbidimetry, and sustained stability over prolonged periods. Observer reliability tests confirmed strong intra- and inter-reader agreements, ensuring consistent and reproducible results. Additionally, the device features a straightforward fabrication process, making it highly scalable and suitable for resource-limited settings. Unlike traditional methods, which often depend on auxiliary devices or complex protocols, the Dist-LFIA provides immediate, equipment-free results. This innovation enhances accessibility to CRP-based diagnostics, facilitating early CVD risk assessment in home settings, remote areas, and under-resourced healthcare environments. Its versatility promises broader applications in diagnostics beyond CVD prediction.