1 Amsterdam UMC, Department of Clinical Chemistry, Vrije Universiteit Amsterdam, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands. m.albersen@vumc.nl.
2 Amsterdam UMC, Department of Pediatric Nephrology, Vrije Universiteit Amsterdam, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
3 Amsterdam UMC, Department of Clinical Chemistry, Vrije Universiteit Amsterdam, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
4 Amsterdam UMC, Department of Pediatric Oncology, Vrije Universiteit Amsterdam, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
5 Prinses Máxima Centrum voor Kinderoncologie, Heidelberglaan 25, 3584 CS, Utrecht, The Netherlands.