The present invention relates to a sensor assembly (1) for body fluids. The sensor assembly (1) comprises: a measurement chamber (2) extending in an axial direction from an inlet end (3) to an outlet end (4), the measurement chamber having a transverse cross-section with side walls (5, 6) defining a chamber width in a horizontal direction, and with top and bottom walls (8, 7) defining a chamber height in a vertical direction, each of the side walls (5, 6), top wall (8) and bottom wall (7) having a respective wall wettability for aqueous solutions; a first sensor (10a-h) adapted to measure a first parameter of body fluids, the first sensor (10 a-h) having a first sensor surface (11a-h) exposed to the inside of the measurement chamber at a first axial position, the first sensor surface (11a-h) having a first wettability for aqueous solutions; and a second sensor (20) adapted to measure a second parameter of body fluids, the second sensor (20) having a second sensor surface (21) exposed to the inside of the measurement chamber (2) at a second axial position upstream or downstream from the first axial position, the second sensor surface (21) having a second wettability for aqueous solutions higher than the first wettability. At the second axial position, the chamber width exceeds the width of the second sensor surface (21), and the measurement chamber has a widening (22) in a horizontal direction as compared to the first axial position.