title: Relevance of EDTA carryover during blood collection.
abstract: BACKGROUND
  The order of draw is regarded as a preanalytical issue to prevent carryover of additives during blood collection. Our objective was to prove the theory of ethylenediaminetetraacetic acid (EDTA) carryover for a closed vacuum system and the influence of EDTA on concentrations of selected biomarkers.
  
  
  METHODS
  To test the carryover of EDTA, a blood collection with tripotassium EDTA (K3EDTA) and subsequent non-additive tubes was simulated using distilled water as substitute for blood. EDTA concentrations were measured by tandem mass spectrometry. Then we added increasing concentrations of EDTA to heparinized blood and measured routine biomarkers, thereby simulating a carryover of EDTA whole blood and pure EDTA, respectively. Additionally, we tested for EDTA contamination and biomarker alteration in samples collected from 10 healthy volunteers by a syringe with subsequent transfer into sample tubes.
  
  
  RESULTS
  No EDTA contamination was detected in samples collected subsequent to a K3EDTA tube when adhering to guidelines of blood sampling. Magnesium, calcium, and potassium levels were altered by artificial K3EDTA whole-blood contamination as well as when adding 1 μL pure K3EDTA. Iron values were altered at EDTA concentrations of 4.4 mmol/L. All other parameters remained unaffected. A slight EDTA carryover was observed in syringe collection and subsequent transfer into EDTA and heparin tubes, however, without any biomarker alteration.
  
  
  CONCLUSIONS
  An EDTA carryover during blood collection using a closed vacuum system is highly unlikely. Even if carryover of EDTA whole blood occurs, an absolute volume larger than 10 μL would be necessary to alter test results. However, contamination of samples with preloaded pure K3EDTA solution by severe neglect of current recommendations in blood collection may significantly alter testing results.
authors.forename: Janne
authors.initials: J
authors.lastname: Cadamuro
authors.forename: Thomas Klaus
authors.initials: TK
authors.lastname: Felder
authors.forename: Hannes
authors.initials: H
authors.lastname: Oberkofler
authors.forename: Cornelia
authors.initials: C
authors.lastname: Mrazek
authors.forename: Helmut
authors.initials: H
authors.lastname: Wiedemann
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Haschke-Becher
mesh_terms: D001800:Blood Specimen Collection / Q000379:methods*; D002853:Chromatography, Liquid; D004492:Edetic Acid / Q000097:blood*; D006801:Humans; D053719:Tandem Mass Spectrometry
chemical_list: D004492:Edetic Acid