Mass Spectrometry for Clinical Toxicology: Therapeutic Drug Management and Trace Element Analysis Alan L. Rockwood, PhD, DABCC*, Kamisha L. Johnson-Davis, PhD, DABCC KEYWORDS • Mass spectrometry • Ionization • Toxicology • Clinical chemistry • Therapeutic drug monitoring • Therapeutic drug management Mass spectrometry is rapidly expanding its role in clinical chemistry. To date, this growth has primarily been in the area of small molecule analysis, though the field now seems set for a rapid growth of protein and peptide analysis. Small molecule analysis applications can be grouped roughly into the analysis of endogenous compounds and the analysis of exogenous compounds. The analysis of exogenous compounds is largely the domain of toxicology, and this is the focus of this article. To limit the scope and, therefore, the length of this article, we focus primarily on 2 general topics within clinical toxicology: therapeutic drug monitoring and trace element analysis. While these 2 topics do not cover the full breadth of mass spectrometry applications in clinical toxicology, omitting, for example, clinical drugs- of-abuse testing and applications supporting poison control programs, we feel that they, nevertheless, provide a fairly representative overview of mass spectrometry in the clinical toxicology lab. TECHNOLOGY AND TECHNIQUE As an aid to those readers who are less familiar with mass spectrometry technology, we also provide a brief tutorial on the technology of mass spectrometry. This section can also be read as an aid in understanding this article and other articles within this volume. Department of Pathology, University of Utah School of Medicine and ARUP Laboratories, 500 Chipeta Way, Salt Lake City, UT 84065, USA * Corresponding author. E-mail address: rockwoal@aruplab.com Clin Lab Med 31 (2011) 407– 428 doi:10.1016/j.cll.2011.07.003 labmed.theclinics.com 0272-2712/11/$ – see front matter © 2011 Elsevier Inc. All rights reserved.