Differences in analytical standardization may lead to misinterpretation and medical flawsJacquelien J. Hillebranda*, Marleen. E. de Langeb, Norah M. van Mellob , Edwin ten Boekelc, Annemieke C. Heijboera,dAffiliations:a Amsterdam University Medical Centers, University of Amsterdam, Endocrine Laboratory, Department of Clinical Chemistry, Amsterdam Gastroenterology Endocrinology Metabolism Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands. j.j.hillebrand@amsterdamumc.nlb Amsterdam University Medical Centers, University of Amsterdam, Department of Obstetrics and Gynecology, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands. m.e.delange@amsterdamumc.nl, n.vanmello@amsterdamumc.nl.c Northwest Clinics Alkmaar, Department Laboratory for Clinical Chemistry, Hematology and Immunology, Wilhelminalaan 12, 1815 JD Alkmaar, The Netherlands. E.ten.boekel@nwz.nld Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Endocrine Laboratory, Department of Clinical Chemistry, Amsterdam Gastroenterology Endocrinology Metabolism, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands. a.heijboer@amsterdamumc.nl