"In the past decade, the development of liquid chromatography mass spectrometry (LC-MS) technology has transformed the paradigm of medical laboratory, and it has become one of the essential analysis platforms for specialized testing, ranging from trace level hormone analysis to clinical laboratory-developed metabolomics and proteomics. The flexibility of LC-MS platform allowed laboratories to provide on-demand laboratory developed tests (LDTs) to meet various clinical needs, some of which may not be immediately available from commercial in vitro diagnostic portfolio. However, the use of LDTs also burdened the laboratories with assay validation, maintenance and regulatory compliance. The complexity and potential pit-fall of LC-MS technology also presented significant and unique challenges to laboratory quality and risk management. Implementation of effective internal quality control and quality assurance procedure was not only essential for delivering accurate and precise results to the patients, but also a useful safeguard mechanism against laboratory errors and performance failure. In this presentation, several real-life examples will be used to illustrate how LC-MS parameters were utilized and interpreted to minimize laboratory errors."