The spinit® cartridge contains several detection zones that include a biological recognition layer (BRL), developed using antibody fragments immobilized on a gold surface. By using different antibody fragments and immobilization strategies, this layer will act as a selective trap for a specific blood biomarker. When the patient's blood passes through the BRL, the targeted biomarker bonds to the immobilized antibody fragments, and this will cause a measurable refractive index change in the SPR signal. When used in conjunction with the cartridge's microfluidic control structures and the spinit® reader SPR sensor, this layer enables us to measure specific blood biomarkers in real-time without any additional labeling reagents.