Our approach enables highly efficient antibody conjugation while dramatically improving upon performance of colorimetric LFIA, by harnessing the synergistic effects of magnetic enrichment and plasmonic signal amplification. Our mpGNS-3-based LFIA system achieves an unprecedented detection limit of 2.24 pg/mL for RVFV nucleoprotein, demonstrating exceptional analytical sensitivity. Moreover, it maintains superior performance in complex biological matrices, successfully detecting RVFV nucleoprotein in blood serum without any pretreatment. This work not only provides a powerful blueprint for designing high-performance POCT diagnostics but also establishes an advanced nanoplatform for ultra-sensitive infectious disease detection. Beyond its immediate applications, our strategy lays the foundation for low-cost, scalable hybrid nanoparticle synthesis, opening new avenues for next-generation colorimetric LFIA platforms with transformative impact in global healthcare and epidemic preparedness.