A sensor assembly, which may be incorporated by a medical electrical lead, includes an insulative body, formed from a biocompatible plastic, and a sensor mounted on a mounting surface of the insulative body. The mounting surface extends distally from a proximal portion of the insulative body in which first and second conductive inserts extend, being spaced apart and isolated from one another. The sensor is coupled to each of the first and second conductive inserts, and the first conductive insert includes a conductor-coupling end extending proximally from the proximal portion of the insulative body. The sensor assembly may further include an electrode extending around the sensor and the insulative body, wherein the electrode includes an aperture approximately aligned with an active surface of the sensor to expose the active surface. A mounting platform assembly for the sensor assembly may include the conductive inserts and the insulative body.