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

Joannes F.M. Jacobs, Katherine A. Turner, Maria Stella Graziani, Jody L. Frinack, Michael W. Ettore, Jillian R. Tate, Ronald A. Booth, Christopher R. McCudden, David F. Keren, Julio C. Delgado, Galina Zemtsovskaja, Robert O. Fullinfaw, Anna Caldini, Theo De Malmanche, Katina Katakouzinos, Matthew Burke, Giovanni Palladini, Sara Altinier, Martina Zaninotto, Gabriella RighettiMarie Therese Melki, Stephen Bell, Maria Alice Vieira Willrich

Research output: Contribution to journalArticle

Abstract

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 <10 g/L. Using spiked sera, we aimed to assess the variability in intact M-protein quantification and LOD across 16 laboratories. 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). 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. 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.

Original languageEnglish
JournalClinical Chemistry and Laboratory Medicine
DOIs
Publication statusAccepted/In press - Jan 1 2020

Fingerprint

Electrophoresis
Limit of Detection
Blood Proteins
Proteins
Capillary electrophoresis
Paraproteinemias
Capillary Electrophoresis
Serum
Uncertainty
Immunoglobulins
Gels
Testing

Keywords

  • accuracy
  • immunofixation
  • immunosubtraction
  • limit of detection
  • monoclonal proteins
  • precision
  • protein electrophoresis

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Biochemistry, medical

Cite this

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. / Jacobs, Joannes F.M.; Turner, Katherine A.; Graziani, Maria Stella; Frinack, Jody L.; Ettore, Michael W.; Tate, Jillian R.; Booth, Ronald A.; McCudden, Christopher R.; Keren, David F.; Delgado, Julio C.; Zemtsovskaja, Galina; Fullinfaw, Robert O.; Caldini, Anna; De Malmanche, Theo; Katakouzinos, Katina; Burke, Matthew; Palladini, Giovanni; Altinier, Sara; Zaninotto, Martina; Righetti, Gabriella; Melki, Marie Therese; Bell, Stephen; Willrich, Maria Alice Vieira.

In: Clinical Chemistry and Laboratory Medicine, 01.01.2020.

Research output: Contribution to journalArticle

Jacobs, JFM, Turner, KA, Graziani, MS, Frinack, JL, Ettore, MW, Tate, JR, Booth, RA, McCudden, CR, Keren, DF, Delgado, JC, Zemtsovskaja, G, Fullinfaw, RO, Caldini, A, De Malmanche, T, Katakouzinos, K, Burke, M, Palladini, G, Altinier, S, Zaninotto, M, Righetti, G, Melki, MT, Bell, S & Willrich, MAV 2020, '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', Clinical Chemistry and Laboratory Medicine. https://doi.org/10.1515/cclm-2019-1105
Jacobs, Joannes F.M. ; Turner, Katherine A. ; Graziani, Maria Stella ; Frinack, Jody L. ; Ettore, Michael W. ; Tate, Jillian R. ; Booth, Ronald A. ; McCudden, Christopher R. ; Keren, David F. ; Delgado, Julio C. ; Zemtsovskaja, Galina ; Fullinfaw, Robert O. ; Caldini, Anna ; De Malmanche, Theo ; Katakouzinos, Katina ; Burke, Matthew ; Palladini, Giovanni ; Altinier, Sara ; Zaninotto, Martina ; Righetti, Gabriella ; Melki, Marie Therese ; Bell, Stephen ; Willrich, Maria Alice Vieira. / 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. In: Clinical Chemistry and Laboratory Medicine. 2020.
@article{31b0437f4e9f44c99d1f0d1adb57056e,
title = "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",
abstract = "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 <10 g/L. Using spiked sera, we aimed to assess the variability in intact M-protein quantification and LOD across 16 laboratories. 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). 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. 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.",
keywords = "accuracy, immunofixation, immunosubtraction, limit of detection, monoclonal proteins, precision, protein electrophoresis",
author = "Jacobs, {Joannes F.M.} and Turner, {Katherine A.} and Graziani, {Maria Stella} and Frinack, {Jody L.} and Ettore, {Michael W.} and Tate, {Jillian R.} and Booth, {Ronald A.} and McCudden, {Christopher R.} and Keren, {David F.} and Delgado, {Julio C.} and Galina Zemtsovskaja and Fullinfaw, {Robert O.} and Anna Caldini and {De Malmanche}, Theo and Katina Katakouzinos and Matthew Burke and Giovanni Palladini and Sara Altinier and Martina Zaninotto and Gabriella Righetti and Melki, {Marie Therese} and Stephen Bell and Willrich, {Maria Alice Vieira}",
year = "2020",
month = "1",
day = "1",
doi = "10.1515/cclm-2019-1105",
language = "English",
journal = "Clinical Chemistry and Laboratory Medicine",
issn = "1434-6621",
publisher = "Walter de Gruyter GmbH",

}

TY - JOUR

T1 - An international multi-center serum protein electrophoresis accuracy and M-protein isotyping study. Part II

T2 - Limit of detection and follow-up of patients with small M-proteins

AU - Jacobs, Joannes F.M.

AU - Turner, Katherine A.

AU - Graziani, Maria Stella

AU - Frinack, Jody L.

AU - Ettore, Michael W.

AU - Tate, Jillian R.

AU - Booth, Ronald A.

AU - McCudden, Christopher R.

AU - Keren, David F.

AU - Delgado, Julio C.

AU - Zemtsovskaja, Galina

AU - Fullinfaw, Robert O.

AU - Caldini, Anna

AU - De Malmanche, Theo

AU - Katakouzinos, Katina

AU - Burke, Matthew

AU - Palladini, Giovanni

AU - Altinier, Sara

AU - Zaninotto, Martina

AU - Righetti, Gabriella

AU - Melki, Marie Therese

AU - Bell, Stephen

AU - Willrich, Maria Alice Vieira

PY - 2020/1/1

Y1 - 2020/1/1

N2 - 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 <10 g/L. Using spiked sera, we aimed to assess the variability in intact M-protein quantification and LOD across 16 laboratories. 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). 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. 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.

AB - 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 <10 g/L. Using spiked sera, we aimed to assess the variability in intact M-protein quantification and LOD across 16 laboratories. 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). 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. 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.

KW - accuracy

KW - immunofixation

KW - immunosubtraction

KW - limit of detection

KW - monoclonal proteins

KW - precision

KW - protein electrophoresis

UR - http://www.scopus.com/inward/record.url?scp=85078114015&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85078114015&partnerID=8YFLogxK

U2 - 10.1515/cclm-2019-1105

DO - 10.1515/cclm-2019-1105

M3 - Article

C2 - 31940285

AN - SCOPUS:85078114015

JO - Clinical Chemistry and Laboratory Medicine

JF - Clinical Chemistry and Laboratory Medicine

SN - 1434-6621

ER -