Enhanced detection and Characterization of M-proteins in multiple myeloma patients using An Agilent AssayMAP Bravo liquid handling system coupled to an LC-QTOF

Matthew Nichols; Chai Phua; Martha Louzada; Benjamin D Hedley; Vipin Bhayana; Ian Chin-Yee; Angela C Rutledge

doi:10.1016/j.clinbiochem.2024.110870

Enhanced detection and Characterization of M-proteins in multiple myeloma patients using An Agilent AssayMAP Bravo liquid handling system coupled to an LC-QTOF

Clin Biochem. 2024 Dec 25:110870. doi: 10.1016/j.clinbiochem.2024.110870. Online ahead of print.

Authors

Matthew Nichols¹, Chai Phua², Martha Louzada², Benjamin D Hedley³, Vipin Bhayana⁴, Ian Chin-Yee⁵, Angela C Rutledge⁴

Affiliations

¹ Department of Pathology and Laboratory Medicine, London Health Sciences Centre and St. Joseph's Health Care London, London, ON, Canada; Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada. Electronic address: matthew.nichols@lhsc.on.ca.
² Division of Hematology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.
³ Department of Pathology and Laboratory Medicine, London Health Sciences Centre and St. Joseph's Health Care London, London, ON, Canada.
⁴ Department of Pathology and Laboratory Medicine, London Health Sciences Centre and St. Joseph's Health Care London, London, ON, Canada; Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.
⁵ Department of Pathology and Laboratory Medicine, London Health Sciences Centre and St. Joseph's Health Care London, London, ON, Canada; Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada; Division of Hematology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.

PMID: 39730070
DOI: 10.1016/j.clinbiochem.2024.110870

Abstract

Background: Mass spectrometry methods are emerging as tools to detect M-proteins in the serum of multiple myeloma patients with increased sensitivity and specificity compared to traditional electrophoretic methods.

Methods: A liquid handling system, the Agilent AssayMAP Bravo, with liquid chromatography high-resolution quadrupole-time-of-flight (LC-QTOF) mass spectrometry to analyze intact light chains was compared to immunofixation electrophoresis (IFE) for M-protein analysis. 210 patient serum samples were analyzed in a split sample comparison (LC-QTOF vs. IFE). LC-QTOF and IFE were interpreted by different individuals in a blinded fashion and results were grouped into four categories: IFE+/QTOF+, IFE+/QTOF-, IFE-/QTOF+, or IFE-/QTOF-.

Results: The LC-QTOF method is able to determine the isotype of M-proteins in a similar fashion to IFE. The estimated limit of detection was ∼ 35 mg/L for adalimumab. For split patient samples, 168 were QTOF+/IFE+, 25 were QTOF-/IFE-, 14 were QTOF+/IFE-, and three were QTOF-/IFE + . Excluding the QTOF+/IFE- results due to the improved sensitivity of the LC-QTOF method, the concordance of LC-QTOF with IFE was ∼ 98 %. The LC-QTOF method also offers improved specificity compared to electrophoretic methods due to inclusion of the accurate mass of the light chains.

Conclusions: The LC-QTOF method was deemed fit for clinical use as a qualitative test with increased sensitivity and specificity compared to IFE. The LC-QTOF can also better resolve therapeutic and multiple myeloma IgG-kappa M-proteins, which present a challenge for electrophoretic methods. Future work will determine suitability of this method as an assessment of minimal residual disease status.

Keywords: Immunofixation electrophoresis; Liquid chromatography; Liquid handler; Mass spectrometry; Myeloma.