An international multi-center serum protein electrophoresis accuracy and M-protein isotyping study. Part II: limit of detection and follow-up of patients with small M-proteins
| Autor: | Christopher R. McCudden, Katina Katakouzinos, Julio C. Delgado, Stephen Bell, Maria Alice V. Willrich, Galina Zemtsovskaja, Theo de Malmanche, Katherine A Turner, David F. Keren, Jody L. Frinack, Matthew Burke, Robert O. Fullinfaw, Ronald A. Booth, Giovanni Palladini, Martina Zaninotto, Jillian R Tate, Maria Stella Graziani, Joannes F M Jacobs, Sara Altinier, Marie Therese Melki, Anna Caldini, Michael W Ettore, Gabriella Righetti |
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| Rok vydání: | 2020 |
| Předmět: |
Immunofixation
monoclonal proteins Myeloma protein Coefficient of variation Cancer development and immune defence Radboud Institute for Molecular Life Sciences [Radboudumc 2] Clinical Biochemistry accuracy immunofixation immunosubtraction limit of detection precision protein electrophoresis Capillary electrophoresis All institutes and research themes of the Radboud University Medical Center medicine Detection limit Chromatography medicine.diagnostic_test biology Biochemistry (medical) General Medicine Gel electrophoresis of proteins Polyclonal antibodies Serum protein electrophoresis biology.protein |
| Zdroj: | Clinical Chemistry and Laboratory Medicine, 58, 4, pp. 547-559 Clinical Chemistry and Laboratory Medicine, 58, 547-559 |
| ISSN: | 1434-6621 |
| Popis: | Background Electrophoretic methods to detect, characterize and quantify M-proteins play an important role in the management of patients with monoclonal gammopathies (MGs). Significant uncertainty in the quantification and limit of detection (LOD) is documented when M-proteins are Methods Sera with normal, hypo- or hyper-gammaglobulinemia were spiked with daratumumab or elotuzumab, with concentrations from 0.125 to 10 g/L (n = 62) along with a beta-migrating sample (n = 9). Laboratories blindly analyzed samples according to their serum protein electrophoresis (SPEP)/isotyping standard operating procedures. LOD and intra-laboratory percent coefficient of variation (%CV) were calculated and further specified with regard to the method (gel/capillary electrophoresis [CZE]), gating strategy (perpendicular drop [PD]/tangent skimming [TS]), isotyping (immunofixation/immunosubtraction [ISUB]) and manufacturer (Helena/Sebia). Results All M-proteins ≥1 g/L were detected by SPEP. With isotyping the LOD was moderately more sensitive than with SPEP. The intensity of polyclonal background had the biggest negative impact on LOD. Independent of the method used, the intra-laboratory imprecision of M-protein quantification was small (mean CV = 5.0%). Low M-protein concentration and high polyclonal background had the strongest negative impact on intra-laboratory precision. All laboratories were able to follow trend of M-protein concentrations down to 1 g/L. Conclusions In this study, we describe a large variation in the reported LOD for both SPEP and isotyping; overall LOD is most affected by the polyclonal immunoglobulin background. Satisfactory intra-laboratory precision was demonstrated. This indicates that the quantification of small M-proteins to monitor patients over time is appropriate, when subsequent testing is performed within the same laboratory. |
| Databáze: | OpenAIRE |
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