title: Experiences with citrate rather than heparin as an anticoagulant for ¹⁸F-FDG labeling of leukocytes.
abstract: In all reported clinical studies with (18)F-FDG-labeled leukocytes, heparin was used as an anticoagulant during labeling. Theoretically, the substitution of heparin with citrate should be advantageous.
  
  
  METHODS
  Blood from healthy controls was sampled in duplicate, anticoagulated with citrate or heparin, and labeled with (18)F-FDG, and the labeling yield was measured. Viability was checked with the trypan blue exclusion technique. Moreover, 4 in vivo PET/CT studies were performed after the reinjection of leukocytes labeled after citrate anticoagulation.
  
  
  RESULTS
  The labeling yields obtained with citrate and heparin were not significantly different (P = 0.447). Viability was greater than or equal to 99%. The quality of the PET/CT studies was excellent. In the in vivo studies, the mean labeling yield was 78%-better than or equal to that reported with heparin as an anticoagulant.
  
  
  CONCLUSIONS
  Citrate is at least as effective as heparin as an anticoagulant, does not (unlike heparin) increase granulocyte activation, and should be the preferred anticoagulant for (18)F-FDG labeling of leukocytes.
authors.affiliation: Department of Nuclear Medicine, Oslo University Hospital, Rikshospitalet, Oslo, Norway. charlotte.eldjarn@oslo-universitetssykehus.no
authors.forename: Charlotte
authors.initials: C
authors.lastname: Eldjarn
authors.forename: Merethe Wigen
authors.initials: MW
authors.lastname: Andersen
authors.forename: Randi Moen
authors.initials: RM
authors.lastname: Forfang
authors.forename: Signe E
authors.initials: SE
authors.lastname: Hagve
authors.forename: Kjell
authors.initials: K
authors.lastname: Rootwelt
mesh_terms: D000925:Anticoagulants / Q000494:pharmacology*; D002478:Cells, Cultured; D019343:Citric Acid / Q000494:pharmacology*; D019788:Fluorodeoxyglucose F18; D006493:Heparin / Q000494:pharmacology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007553:Isotope Labeling / Q000379:methods; D007962:Leukocytes / Q000000981:diagnostic imaging* / Q000187:drug effects*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity
chemical_list: D000925:Anticoagulants; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D019343:Citric Acid; D006493:Heparin