Mass spectrometry (MS) once had very specific applications in the clinical lab, but its uses have since expanded beyond screening newborns, analyzing steroid hormones, and confirming drug abuse, write Paul J. Jannetto, PhD, and Robert L. Fitzgerald in Clinical Chemistry’s special MS-focused issue.

The method “is now being used in almost all areas of laboratory medicine,” according to Jannetto, co-director of the Toxicology and Drug Monitoring Laboratory at the Mayo Clinic in Rochester, Minnesota, and Fitzgerald, director of toxicology and associate director of clinical chemistry at the University of California, San Diego School of Medicine.

Several technologies have advanced MS’ status as a viable tool in the clinical lab, such as electrospray ionization (ESI) combined with high-performance liquid chromatography (LC)-tandem MS (MS/MS), which has facilitated sample preparation schemes. In addition, the development of matrix-assisted laser desorption ionization/time of flight (MALDI-TOF) MS, “has allowed for the rapid identification analysis of microbes,” the authors state.

Other MS-based platforms are able to quickly identify microbes directly from biological samples, using ESI “to identify PCR products amplified using generic primers. While not currently [Food and Drug Administration]-approved, this approach combines molecular specificity with an 8-hour time to identification,” the authors explain.

MS has also been implicated in a promising area of research that involves “omics” technologies: the metabolomic, lipidomic, and proteomic analyses of clinical samples.

In addition to emerging uses, MS is becoming an increasingly popular method for measuring testosterone and other sex steroids, due to its analytical specificity and sensitivity compared with traditional immunoassays, according to Jannetto and Fitzgerald.

MS also offers advantages over traditional immunoassays in measuring thyroglobulin. Antithyroglobulin autoantibodies can interfere with the thyroglobulin measurement results of traditional assays. However, “using tryptic digestion with peptide-specific immunocapture, LC-MS/MS quantification of the thyroglobulinspecific peptides is able to overcome the interference of antithyroglobulin autoantibodies,” Jannetto and Fitzgerald emphasize.

The authors believe MS has a promising future in laboratory medicine. Institutions are developing novel ways of using the technology. Purdue University, for instance, is testing a miniaturized transportable MS system that might be useful in point-of-care settings. Outside of the clinical lab, the Imperial College of London is using MS in operating rooms to help surgeons detect the presence of cancerous tissue.

Pick up the January issue of Clinical Chemistry to learn more about current and future uses of MS, as well as the benefits and challenges associated with this durable technology.