title: Sodium citrate blood contamination by K2 -ethylenediaminetetraacetic acid (EDTA): impact on routine coagulation testing.
abstract: BACKGROUND
  The potential cross-contamination of additives between primary blood tubes is a well-known problem during sample collection. The aim of this study was to assess the impact of citrated blood contamination with different amounts of dipotassium ethylenediaminetetraacetic (K2 EDTA blood) on activated partial thromboplastin time (APTT), prothrombin time (PT), and fibrinogen.
  
  
  METHODS
  Blood was collected from 15 ostensibly healthy volunteers into four 0.109 m citrate blood tubes followed by one K2 EDTA blood tube. The citrate tubes of each subject were pooled and divided in five aliquots. The whole blood of the K2 EDTA tube was then added in scalar amounts to autologous citrated blood aliquots, to obtain K2 EDTA contamination ranging from 0% to 43%, and thus mimic potential pre-analytical contamination.
  
  
  RESULTS
  A statistically and clinically significant prolongation was observed for both APTT and PT between 29% and 43% K2 EDTA contamination, whereas the decrease of fibrinogen values became statistically and clinically significant at 43% K2 EDTA contamination.
  
  
  CONCLUSIONS
  The results of this investigation show that contamination of citrated blood with as much as 29% of K2 EDTA blood generates a significant bias in results of routine clotting assays. This has serious implications for patient safety and management.
authors.affiliation: Laboratory of Clinical Biochemistry, Department of Life and Reproduction Sciences, University of Verona, Verona, Italy; Post-Graduate Program of Pharmaceutical Sciences, Department of Clinical Analyses, Federal University of Parana, Curitiba, Parana, Brazil.
authors.forename: G
authors.initials: G
authors.lastname: Lima-Oliveira
authors.forename: G L
authors.initials: GL
authors.lastname: Salvagno
authors.forename: E
authors.initials: E
authors.lastname: Danese
authors.forename: E J
authors.initials: EJ
authors.lastname: Favaloro
authors.forename: G C
authors.initials: GC
authors.lastname: Guidi
authors.forename: G
authors.initials: G
authors.lastname: Lippi
mesh_terms: D000328:Adult; D000368:Aged; D000925:Anticoagulants; D001780:Blood Coagulation Tests / Q000379:methods / Q000592:standards*; D001800:Blood Specimen Collection / Q000379:methods; D002951:Citrates; D004492:Edetic Acid; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D000077559:Sodium Citrate; D013048:Specimen Handling
chemical_list: D000925:Anticoagulants; D002951:Citrates; D000077559:Sodium Citrate; D004492:Edetic Acid
keywords: EDTA; Preanalytical variability; contamination; patient safety