Depending on the age of the child, one to 11 mL of whole blood is collected in Serum Separator Tubes (SST, BD) by trained paediatric phlebotomists using standardized conditions. Specific collection tubes may also be used depending on the labortaory test of interest (e.g. KEDTA, LiHep, NaCitrate, Royal Blue Top). Blood samples are centrifuged at 4000 rpm for 10 minutes within eight hours of collection, aliquoted into 0.5 mL cryovials, and stored at –80°C. All samples are de-identified prior to storage.
Samples have been analyzed on several analytical platforms, including analyzers from Abbott Diagnostics, Ortho Clinical Diagnostics, DiaSorin, Roche Diagnostics, Beckman Coulter Diagnostics, Siemens Healthineers, as well as Liquid Chromatography and Tandem Mass Spectrometry (LC-MS/MS), Inductively Coupled Plasma Mass Spectrometry (ICP-MS), and High-Performance Liquid Chromatography (HPLC) techniques. Analytical methods are controlled according to manufacturers’ instructions via preventive maintenance and function checks, calibration, and quality control. All tests are subjected to automated interference analysis for hemolysis, icterus, and turbidity.