title: Dried blood spot validation of five immunosuppressants, without hematocrit correction, on two LC-MS/MS systems.
abstract: OBJECTIVE
  Hematocrit (Ht) effects remain a challenge in dried blood spot (DBS) sampling. The aim was to develop an immunosuppressant DBS assay on two LC-MS/MS systems covering a clinically relevant Ht range without Ht correction.
  
  
  RESULTS
  The method was partially validated for tacrolimus, sirolimus, everolimus, cyclosporin A and fully validated for mycophenolic acid on an Agilent and Thermo LC-MS/MS system. Bias caused by Ht effects were within 15% for all immunosuppressants between Ht levels of 0.23 and 0.48 l/l. Clinical validation of DBS versus whole blood samples for tacrolimus and cyclosporin A showed no differences between the two matrices.
  
  
  CONCLUSIONS
  A multiple immunosuppressant DBS method without Ht correction, has been validated, including a clinical validation for tacrolimus and cyclosporin A, making this procedure suitable for home sampling.
authors.affiliation: University of Groningen, Department of Clinical Pharmacy & Pharmacology, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Remco A
authors.initials: RA
authors.lastname: Koster
authors.affiliation: University of Groningen, Department of Clinical Pharmacy & Pharmacology, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Herman
authors.initials: H
authors.lastname: Veenhof
authors.affiliation: University of Groningen, Department of Clinical Pharmacy & Pharmacology, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Rixt
authors.initials: R
authors.lastname: Botma
authors.affiliation: University of Groningen, Department of Clinical Pharmacy & Pharmacology, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Alle Tjipke
authors.initials: AT
authors.lastname: Hoekstra
authors.affiliation: University of Groningen, Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Stefan P
authors.initials: SP
authors.lastname: Berger
authors.affiliation: University of Groningen, Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Stephan Jl
authors.initials: SJ
authors.lastname: Bakker
authors.affiliation: University of Groningen, Department of Clinical Pharmacy & Pharmacology, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Jan-Willem C
authors.initials: JC
authors.lastname: Alffenaar
authors.affiliation: University of Groningen, Department of Clinical Pharmacy & Pharmacology, University Medical Center Groningen, Groningen, The Netherlands.|University of Groningen, Department of Pharmacy, Section Pharmacokinetics, Toxicology & Targeting, Groningen, The Netherlands.
authors.forename: Daan J
authors.initials: DJ
authors.lastname: Touw
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D016572:Cyclosporine / Q000097:blood; D059788:Dried Blood Spot Testing / Q000379:methods*; D016903:Drug Monitoring / Q000379:methods*; D000068338:Everolimus / Q000097:blood; D006400:Hematocrit; D006801:Humans; D007166:Immunosuppressive Agents / Q000097:blood*; D009173:Mycophenolic Acid / Q000097:blood; D020123:Sirolimus / Q000097:blood; D016559:Tacrolimus / Q000097:blood; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D007166:Immunosuppressive Agents; D016572:Cyclosporine; D000068338:Everolimus; D009173:Mycophenolic Acid; D020123:Sirolimus; D016559:Tacrolimus
keywords: DBS; clinical validation; cyclosporine A; dried blood spot; everolimus; hematocrit effect; immunosuppressants; mycophenolic acid; sirolimus; tacrolimus