scope:

This document provides an introduction to, and guidance, resources, and references for, the use of mass spectrometry (MS) in the clinical laboratory. It serves to illuminate specific issues in mass spectrometric analyses that must be considered when the technology is applied to clinical testing. This guideline aims to educate both the practitioners of MS and the medical professionals who use the results produced by the instruments for the diagnosis, characterization, or monitoring of disease. Through knowledge of this material, the medical professional will better understand why MS may be preferred for a clinical application. They will also become more informed consumers when selecting a diagnostic laboratory to provide MS services. This document is also intended to be a basic resource for instrument manufacturers; regulatory agencies; and those responsible for developing standards, implementing policy, and teaching.

Selected examples of "routinely utilized clinical assays" are used to describe the fundamental principles of MS. These examples are primarily from tests for small molecules and metabolites. There is also a brief discussion of the MS analysis of other analytes that are either not common in clinical chemistry application at the time of this writing or are highly specialized, warranting their own document. These analytes include elements, peptides, proteins, and other biopolymers, including oligonucleotides.

A description of all current clinical applications of MS is beyond the scope of this document. Therefore, the goal of this guideline is to provide a basic understanding of the technology and how it should be used in the clinical laboratory with an emphasis on:

• advantages and disadvantages;

• precautions required in its use;

• quality control awareness;

• assay verification/validation;

• approaches to reporting results; and

• communication of the data.

Portions of published and validated clinical methods are discussed in more detail to illustrate these concepts when required.