This paper introduces a preliminary study about using a health monitor (HM) to contribute towards production and on-line testing of System in Package (SiP) that contain MEMS functions. The HM serves as a central unit for the test of both the structure and critical functions within the SiP. The study includes the review of existing test solution which could be in-tegrated in the HM and some initial ideas to test the MEMS functions as typically, BIST is not normally supported by these devices. A SiP RF transceiver is used as a case study. An evaluation of the feasibility of implementing a HM for testing a MEMS switch is presented. Preliminary simulation results obtained by superimposing a low frequency signal into the bias of the switch are encouraging.