In this paper, we discuss the use of non-intrusive sensors to enable a built-in test for a 65nm RF LNA. The non-intrusive sensors consist of single layout components copied from the topology of the LNA and dummy analog stages formed by identical components used in the topology of the LNA. The sensors are placed in close physical proximity to the LNA such that the sensor measurements track the performances of the LNA by virtue of die-to-die and correlated within-die process variations. In this way, the alternate test paradigm is used to infer the performances from the sensor measurements. Although the correlation between sensor measurements and performances is negatively affected by the uncorrelated within-die variations, we show that the correlation still holds strong even for the advanced 65nm technology node where this type of variations is more pronounced. In addition, we show that instead of using dummy area-hungry inductors to monitor inductance variability, we can obtain the same level of correlation by monitoring instead the sheet resistances of the metal lines that form the coil of the inductors.