Austrian Association for Quality Assurance and Standardization of Medical and Diagnostic Tests (ÖQUASTA), UK National External Quality Assessment Scheme (UK NEQAS) for Haematology, University Hospitals Birmingham NHS Foundation Trust, Centre Toulousain pour le Contrôle de qualité en Biologie clinique (CTCB), Royal College of Pathologists of Australasia Quality Assurance Program, FTC Forensic Toxicology Laboratory, MVZ Ärztliche Laboratorien München-Land GmbH, Independent, Laboratoire National de Métrologie et d’Essais (LNE), KU Leuven, FTC Forensic Toxicology Laboratory, Reference Institute for Bioanalytics, Erasmus University Rotterdam (EUR), LGC, Ltd., NGO AQALM, INSTAND e.V. Society for Promoting Quality Assurance in Medical Laboratories, GBD Gesellschaft für Biotechnologische Diagnostik mbH, Reference Institute for Bioanalytics, KU Leuven, Technische Universität München (TUM), Swiss Center for Quality Control (CSCQ), Technology University of Braunschweig, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń - Department of Laboratory Medicine, Careggi University Hospital of Florence, RISE Research Institutes of Sweden, The Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Paul-Ehrlich-Institut, University of Ljubljana - University Medical Centre Ljubljana, INSTAND e.V. Society for Promoting Quality Assurance in Medical Laboratories, The Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Radboud University - Radboud University Medical Center, Medical University Vienna, Institut für Qualitätssicherung in der Virusdiagnostik - IQVD GmbH, University of British Columbia (UBC) - Department of Pathology and Laboratory Medicine and University of British Columbia (UBC) - Department of Pathology and Laboratory Medicine

National Institute for Public Health and the Environment (RIVM) - Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM) - Centre for Infectious Disease Control, Star-shl Medical Diagnostic Center, Zuyderland Medical Center, Tergooi Medical Center, Rijnstate Hospital, University of Groningen - University Medical Center Groningen, Result Laboratorium, Maastricht University, Haaglanden Medical Center, Erasmus University Rotterdam (EUR), Dijklander Hospital, Public Health Service of Amsterdam, Maasstad Hospital, Isala Zwolle, Meander Medical Centre, Radboud University Nijmegen - Radboud University Medical Center, Deventer Hospital, Regional Public Health Laboratory Kennemerland, Regional Public Health Laboratory Kennemerland, Antonius Hospital, Laboratory for Medical Microbiology and Public Health (LabMicTA), Elisabeth-Tweesteden Hospital, Diakonessen Hospital, Leiden University - Leiden University Medical Center (LUMC), Canisius Wilhelmina Hospital, University of Amsterdam - Amsterdam UMC, National Institute for Public Health and the Environment (RIVM) - Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM) - Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM) and National Institute for Public Health and the Environment (RIVM) - Centre for Infectious Disease Control