A magnetic measurement system for measuring a concentration of specific bio-particles through a sensitive detection of magnetic particle labels comprising: - an aptamer-based magnetic hybrid Anisotropic Magnetoresistive/ Planar Hall Magnetoresistive (AMR/PHR) sensor having: • an active surface on which at least one magnetic particle is ready to be or is closely bound through a sandwich-type aptamer structure that includes a captured unitary bio-particle, the active surface including a magnetic track with a closed loop shape, • a first current terminal and a second terminal, forming a pair of current terminals (30, 32) facing each other and contacting with the closed loop magnetic track, • a first voltage terminal and a second voltage terminal forming a pair of voltage terminals facing each other and contacting with the closed loop magnetic track, - an electrical bias current source configured to inject a bias current in the magnetic track, the electrical source being connected between the first and second current terminals (30, 32), and - a voltage measurement device connected between the first and second voltage terminals (34, 36) measuring a differential voltage V MR between the pair of voltage terminals (34, 36), - a magnetic element for applying an actual DC constant magnetic field on the magnetic track at a predetermined amplitude; - a signal processing device (20; 320) configured to deduce at least one physical quantity based on the differential voltage and representative of the bio-particles concentration characterized in that the magnetic measurement system is being configured to choose the actual amplitude of the applied DC constant magnetic field to be closely located in a vicinity (218, 210) of an optimum amplitude of the permanent DC magnetic field comprised in a set of two optimum values H1, H2 of the permanent DC magnetic field, each optimum value H1, H2 maximizing locally the absolute value of a first quantity H ⋅ ∂ V MR ∂ H, where H is the amplitude of the applied magnetic field and ∂ V MR ∂ H is the derivate of the differential voltage with respect to the magnetic field at the applied field H. - an aptamer-based magnetic hybrid Anisotropic Magnetoresistive/ Planar Hall Magnetoresistive (AMR/PHR) sensor having: • an active surface on which at least one magnetic particle is ready to be or is closely bound through a sandwich-type aptamer structure that includes a captured unitary bio-particle, the active surface including a magnetic track with a closed loop shape, • a first current terminal and a second terminal, forming a pair of current terminals (30, 32) facing each other and contacting with the closed loop magnetic track, • a first voltage terminal and a second voltage terminal forming a pair of voltage terminals facing each other and contacting with the closed loop magnetic track, • an active surface on which at least one magnetic particle is ready to be or is closely bound through a sandwich-type aptamer structure that includes a captured unitary bio-particle, the active surface including a magnetic track with a closed loop shape, • a first current terminal and a second terminal, forming a pair of current terminals (30, 32) facing each other and contacting with the closed loop magnetic track, • a first voltage terminal and a second voltage terminal forming a pair of voltage terminals facing each other and contacting with the closed loop magnetic track, - an electrical bias current source configured to inject a bias current in the magnetic track, the electrical source being connected between the first and second current terminals (30, 32), and - a voltage measurement device connected between the first and second voltage terminals (34, 36) measuring a differential voltage V MR between the pair of voltage terminals (34, 36), - a magnetic element for applying an actual DC constant magnetic field on the magnetic track at a predetermined amplitude; - a signal processing device (20; 320) configured to deduce at least one physical quantity based on the differential voltage and representative of the bio-particles concentration