Abstract
The use of mass spectrometric (MS) techniques is becoming widespread in clinical laboratories. The main techniques for analysis of molecular targets that are relevant to clinical chemistry include gas chromatography (GC) coupled with electron ionization (EI) MS and high-performance liquid chromatography (HPLC) coupled with electrospray ionization (ESI) MS. The analytes targeted by these hyphenated techniques include amino, organic, and fatty acids, steroids and hormones, and drugs and metabolites in addition to others. MS-aided methods are complementary to conventional methods such as immunoassays, and in some cases provide better performance. Nonetheless, MS requires bulky and costly instrumentation. The clinical matrices analyzed by MS methods include blood, urine, meconium, feces, cerebrospinal fluid, umbilical cords, and liver tissue. In the past few years, a number of MS methods were disclosed that targeted unconventional clinical matrices such as sweat, saliva, hair, nails, and tears. Moreover, matrix-assisted laser desorption/ionization (MALDI) MS is an efficient technique for microorganism identification in clinical matrices. MS imaging (MSI), ion mobility spectrometry (IMS), and mass cytometry enable highly selective analysis of molecules in body fluids, tissues, and cells in certain applications, but their use is mainly limited to research laboratories.