CLSI C62—Liquid Chromatography–Mass Spectrometry Methods provides guidance for the development and validation of liquid chromatography–mass spectrometry (LC-MS) methods in the medical laboratory. CLSI C62 is intended to support the development, validation, implementation, and maintenance of accurate and precise clinical assays through guidance for evaluating interferences, assay performance, and other pertinent characteristics specific to chromatographic and mass spectrometric techniques. CLSI C62 is intended for laboratorians responsible for the development and validation of mass spectrometry (MS)–based assays, health care providers who may use these assays for patient care decisions, external quality assessment programs, regulatory agencies, and manufacturers of MS instrumentation and reagent kits. CLSI C62 is limited to discussion of LC-MS and focuses on the steps for the development of a method, eg, whether the analyte is a drug, hormone, peptide, or protein.

CLSI C62 provides an introduction to and guidance for method development, validation, verification, and postimplementation monitoring of clinical applications using liquid chromatography–mass spectrometry (LC-MS), including the detection, diagnosis, and monitoring of diseases or disorders. Although LC-MS can also be used for untargeted qualitative analyses, the focus of CLSI C62 is on the use of this technology for targeted detection and/ or quantification of clinically relevant analytes. Additionally, although there are commercial and research methods that enable direct injection without chromatography for rapid analyses, CLSI C62 is exclusively focused on LCMS, including liquid chromatography–tandem mass spectrometry (LC-MS/MS). The purpose of CLSI C62 is to educate developers, clinical LC-MS practitioners, and health care providers who might use these test methods for patient care decisions on the benefits and limitations of LC-MS methods used in the medical laboratory, as well as provide a practical guide for the development and implementation of LC-MS–based clinical applications. It is intended to serve not only as a companion to CLSI C50 which serves as general guidance for mass spectrometry (MS) in the medical laboratory, but also to provide an enhanced focus on methods, recommended practices, and instrumentation related to LC-MS. CLSI C62 is also intended as a resource for instrument manufacturers, manufacturers of LC-MS reagents, regulatory agencies, and educators, as well as individuals responsible for developing laboratory standards and policy. It serves as a foundational document for CLSI C64 which provides specific guidance on quantitative protein MS methods. 

A description of all current clinical applications of LC-MS, as well as pertinent information regarding development, validation, and verification of these methods, is beyond the scope of CLSI C62. As such, the reader is directed to appropriate existing resources wherever possible. In providing guidance for LC-MS method development, validation, and implementation, CLSI C62 focuses on: 

• Important features of LC-MS instrumentation
• Preexamination factors that can affect assay performance and utility
• Assay calibration • Analytical variables important in method development
• Assay validation and verification
• QA and QC
• Postimplementation method monitoring 

The intended users of CLSI C62 are medical laboratorians, instrument manufacturers, regulatory agencies, health care providers, external quality assessment programs, and manufacturers of testing components or kits.