Pitfalls Associated with the Use of Liquid Chromatography–Tandem Mass Spectrometry in the Clinical Laboratory

Abstract

BACKGROUND Novel mass spectrometric techniques such as atmospheric pressure ionization and tandem mass spectrometry have substantially extended the spectrum of clinical chemistry methods during the past decade. In particular, liquid chromatography tandem–mass spectrometry (LC-MS/MS) has become a standard tool in research laboratories as well as in many clinical laboratories. Although LC-MS/MS has features that suggest it has a very high analytical accuracy, potential sources of inaccuracy have recently been identified. CONTENT The sources of inaccuracy in LC-MS/MS methods used in the routine quantification of small molecules are described and discussed. Inaccuracy of LC-MS/MS methods can be related to the process of ionization through the insource transformation of conjugate metabolites or target analytes and may also be attributable to ionization matrix effects that have a differential impact on target analytes and internal-standard compounds. Inaccuracy can also be associated with the process of ion selection, which mainly occurs when compounds from the sample matrix share mass transitions with a target analyte. In individual assays, most potential sources of inaccuracy can be controlled by sufficient LC separation–based sample workup before MS analysis. SUMMARY LC-MS/MS methods should undergo rigorous and systematic validation before introduction into patient care.

High mass accuracy assay for trimethylamine N-oxide using stable-isotope dilution with liquid chromatography coupled to orthogonal acceleration time of flight mass spectrometry with multiple reaction monitoring

“…Next steps for this transition will include the need for high mass accuracy instrumentation to overcome interferences that can affect the accuracy of measurement with 14 some nominal mass MRM systems [18,[26][27]. Initial exploration of this technology has already been done in toxicology laboratories [28].…”

“…LC-MS/MS-MRM on triple quadrupoles is increasingly being seen as a gold standard for measurement of molecules in clinical laboratories [17]. Whilst limitations exist with these approaches [18], the selectivity and wide dynamic range leads to a high level of sensitivity which has benefitted many different fields. For many analytes, sufficient selectivity is delivered by triple quadrupole instruments.…”

Vitamin D – challenges in diagnosing and monitoring of hypovitaminosis D / Vitamin D – izazovi u dijagnozi i praćenju hipovitaminoze D

“…Yet, an application of LC-MS/MS in laboratory medicine is still based on individual instrument installation and method implementation with a very poor standardization of instrumentation. With such selfdeveloped and not fully automated tests run on highly complex instruments, the risk of systematic bias is given for several reasons, also including many potential sources of gross errors (22,23).…”

Analytical Performance of LC-MS/MS Method for Simultaneous Determination of Five Steroids in Serum

“…The reliable and simultaneous analysis of steroid hormones panel is a powerful tool for investigation of steroid hormone status, which is relevant for the diagnosis and treatment of a variety of clinical disorders like adrenal insufficiency and congenital adrenal hyperplasia (CAH) [1][2][3][4][5]. Due to the low levels of serum steroids metabolites and chemical similarity, analysis of this kind of compounds has been a challenge [1].…”

“…Tandem mass spectrometry methods with atmospheric pressure chemical ionization (APCI) ionization were developed in 1990s [4] and during the past two decades, LC-MS/MS techniques showed an increased usage in clinical laboratories, mainly to small molecules analyses [5,6]. The accurate measurement of hormones is the pivot of modern endocrinology and so lays the importance of method validation to demonstrate characteristics of reprodutibility, accuracy and specificity [7,8].…”