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The EuroFlow PIDOT external quality assurance scheme: enhancing laboratory performance evaluation in immunophenotyping of rare lymphoid immunodeficiencies

  • Jana Neirinck , Malicorne Buysse , Naděžda Brdickova , Martín Perez-Andres , Ciel De Vriendt , Tessa Kerre , Filomeen Haerynck , Xavier Bossuyt , Jacques J.M. van Dongen , Alberto Orfao , Mattias Hofmans , Carolien Bonroy and Tomas Kalina EMAIL logo
Published/Copyright: October 21, 2024
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Clinical Chemistry and Laboratory Medicine (CCLM)
From the journal Clinical Chemistry and Laboratory Medicine (CCLM) Volume 63 Issue 3

Abstract

Objectives

The development of External Quality Assessment Schemes (EQAS) for clinical flow cytometry (FCM) is challenging in the context of rare (immunological) diseases. Here, we introduce a novel EQAS monitoring the primary immunodeficiency Orientation Tube (PIDOT), developed by EuroFlow, in both a ‘wet’ and ‘dry’ format. This EQAS provides feedback on the quality of individual laboratories (i.e., accuracy, reproducibility and result interpretation), while eliminating the need for sample distribution.

Methods

In the wet format, marker staining intensities (MedFIs) within landmark cell populations in PIDOT analysis performed on locally collected healthy control (HC) samples, were compared to EQAS targets. In the dry format, participants analyzed centrally distributed PIDOT flow cytometry data (n=10).

Results

We report the results of six EQAS rounds across 20 laboratories in 11 countries. The wet format (212 HC samples) demonstrated consistent technical performance among laboratories (median %rCV on MedFIs=34.5 %; average failure rate 17.3 %) and showed improvement upon repeated participation. The dry format demonstrated effective proficiency of participants in cell count enumeration (range %rCVs 3.1–7.1 % for the major lymphoid subsets), and in identifying lymphoid abnormalities (79.3 % alignment with reference).

Conclusions

The PIDOT-EQAS allows laboratories, adhering to the standardized EuroFlow approach, to monitor interlaboratory variations without the need for sample distribution, and provides them educational support to recognize rare clinically relevant immunophenotypic patterns of primary immunodeficiencies (PID). This EQAS contributes to quality improvement of PID diagnostics and can serve as an example for future flow cytometry EQAS in the context of rare diseases.

Keywords: external quality assurance; flow cytometry; EuroFlow; primary immunodeficiencies; standardization
Corresponding author: Tomas Kalina, CLIP Cytometry, Department of Pediatric Hematology and Oncology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic, E-mail:
Mattias Hofmans, Carolien Bonroy and Tomas Kalina share senior authorship.

Funding source: Charles University Research Centre program

Award Identifier / Grant number: UNCE/24/MED/003

Funding source: Czech Republic Ministry of Health

Award Identifier / Grant number: NU23-07-00170

Funding source: Fonds Wetenschappelijk Onderzoek

Award Identifier / Grant number: 11L2822N

Award Identifier / Grant number: T000119N

Funding source: European Union – Next Generation EU

Award Identifier / Grant number: LX22NPO5102

Funding source: Instituto de Salud Carlos III (ISCIII)

Award Identifier / Grant number: PI20/01712

Acknowledgments

All members of the EuroFlow consortium and participating laboratories are acknowledged for their contribution to the network and for fruitful discussions.

  1. Research ethics: This study was approved by Ghent University Hospital Ethics Committee, Ghent, Belgium (BC-07300; 2016/1138) and was conducted in accordance with the Declaration of Helsinki (as revised in 2013).

  2. Informed consent: Informed consent was obtained from all individuals included in this study, or their legal guardians or wards.

  3. Author contributions: ToK, CB, MH, AO and JJMvD contributed to the conception and design of the study. For the wet format, CB, MH, XB, MPA, AO, and JJMvD provided flow cytometric data for reference data set. For the dry format, the team of the University Hospital Ghent (CB, MH, MB, and JN) was assigned as the reference lab and was responsible for the pre-round preparation, including PID case selection, data acquisition, quality control of FCS files, data analysis and interpretation. TeK, CDV and FH (University Hospital Ghent) provided the clinical data of the PID cases. In the post-round phase, ToK, and NB were responsible for the collection of the participants’ results via the EuroFlow EQAS website and the generation of the EQAS certificates. JN and MB were assigned as second reviewer of the EQAS certificates and generated the summary reports under the supervision of MH, CB and ToK. JN drafted the original draft manuscript. MB, MH, CB, XB, MPA, AO, NB, and ToK revised and edited the original draft of the manuscript. All authors contributed to the manuscript revision, read and approved the submitted version.

  4. Use of Large Language Models, AI and Machine Learning Tools: None declared.

  5. Conflict of interest: The authors state no conflict of interest.

  6. Research funding: This study has been supported by an FWO TBM grant (Research Foundation – Flanders. T000119N). JN is a PhD fellow of the Research Foundation Flanders (FWO 11L2822N). TK was supported by the project NU23-07-00170 of the Czech Republic Ministry of Health, Charles University Research Centre program No. UNCE/24/MED/003 and the European Union – Next Generation EU – program No. LX22NPO5102. MPA received funding from the Instituto de Salud Carlos III (ISCIII) through the project “PI20/01712” and co-founded by the European Union. The coordination and innovation processes of this study were supported by the EuroFlow Consortium.

  7. Data availability: The raw data can be obtained on request from the corresponding author.

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Supplementary Material

This article contains supplementary material (https://doi.org/10.1515/cclm-2024-0749).

Received: 2024-06-26
Accepted: 2024-09-24
Published Online: 2024-10-21
Published in Print: 2025-02-25

© 2024 Walter de Gruyter GmbH, Berlin/Boston

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https://doi.org/10.1515/cclm-2024-0749
Keywords for this article
external quality assurance; flow cytometry; EuroFlow; primary immunodeficiencies; standardization

Articles in the same Issue

  1. Frontmatter
  2. Editorials
  3. Multi-cancer early detection: searching for evidence
  4. High sensitivity cardiac troponin assays, rapid myocardial infarction rule-out algorithms, and assay performance
  5. Reviews
  6. Consensus statement on extracellular vesicles in liquid biopsy for advancing laboratory medicine
  7. Copeptin as a diagnostic and prognostic biomarker in pediatric diseases
  8. Opinion Papers
  9. The Unholy Grail of cancer screening: or is it just about the Benjamins?
  10. Critical appraisal of the CLSI guideline EP09c “measurement procedure comparison and bias estimation using patient samples”
  11. Tumor markers determination in malignant pleural effusion: pearls and pitfalls
  12. Contribution of laboratory medicine and emerging technologies to cardiovascular risk reduction via exposome analysis: an opinion of the IFCC Division on Emerging Technologies
  13. Guidelines and Recommendations
  14. Recommendations for European laboratories based on the KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease
  15. Genetics and Molecular Diagnostics
  16. Expanded carrier screening for 224 monogenic disease genes in 1,499 Chinese couples: a single-center study
  17. General Clinical Chemistry and Laboratory Medicine
  18. How do experts determine where to intervene on test ordering? An interview study
  19. New concept for control material in glucose point-of-care-testing for external quality assessment schemes
  20. Vitamin B12 deficiency in newborns: impact on individual’s health status and healthcare costs
  21. Analytical evaluation of eight qualitative FIT for haemoglobin products, for professional use in the UK
  22. Colorimetric correcting for sample concentration in stool samples
  23. Reference Values and Biological Variations
  24. Assessment of canonical diurnal variations in plasma glucose using quantile regression modelling and Chronomaps
  25. Inconsistency in ferritin reference intervals across laboratories: a major concern for clinical decision making
  26. Establishing the TSH reference intervals for healthy adults aged over 70 years: the Australian ASPREE cohort study
  27. Hematology and Coagulation
  28. The EuroFlow PIDOT external quality assurance scheme: enhancing laboratory performance evaluation in immunophenotyping of rare lymphoid immunodeficiencies
  29. Clinical value of smear review of flagged samples analyzed with the Sysmex XN hematology analyzer
  30. Cardiovascular Diseases
  31. Evidence for stability of cardiac troponin T concentrations measured with a high sensitivity TnT test in serum and lithium heparin plasma after six-year storage at −80 °C and multiple freeze-thaw cycles
  32. Letters to the Editor
  33. Impact of high-sensitivity cardiac troponin I assay imprecision on the safety of a single-sample rule-out approach for myocardial infarction
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