1 Austrian Association for Quality Assurance and Standardization of Medical and Diagnostic Tests (ÖQUASTA), Vienna A-1090, Austria. Electronic address: christoph.buchta@oequasta.at.
2 IQVD GmbH, Institut für Qualitätssicherung in der Virusdiagnostik, Berlin, Germany.
3 Max von Pettenkofer Institute & Gene Center, Virology, National Reference Center for Retroviruses, LMU München, Munich, Germany.
4 Canadian Microbiology Proficiency Testing Program (CMPT) Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada.
5 Austrian Association for Quality Assurance and Standardization of Medical and Diagnostic Tests (ÖQUASTA), Vienna A-1090, Austria; Central Institute of Clinical and Chemical Laboratory Diagnostics, University Hospital of Innsbruck, Innsbruck, Austria.