title: Postural change during venous blood collection is a major source of bias in clinical chemistry testing.
abstract: BACKGROUND
  To investigate the influence of different phlebotomy postures on clinical chemistry testing.
  
  
  METHODS
  Nineteen volunteers were recruited from the laboratory staff. A first set of samples was drawn after 25 min of resting in supine position, a second after 20 min in sitting position, and a third after 20 min in upright position. Clinical chemistry testing was performed on Roche Cobas C501.
  
  
  RESULTS
  The plasma volume change (PVC) was -3.4% from supine to sitting, -14.1% from supine to standing and -9.7% from sitting to standing. Compared to quality specifications for bias, hemoglobin, hematocrit, albumin and total proteins exhibited meaningful increases from supine to sitting, whereas meaningful increases were observed for hemoglobin, hematocrit, albumin, alkaline phosphatase (ALP), amylase, aspartate aminotransferase (AST), total bilirubin, calcium, total and high-density lipoprotein (HDL) cholesterol, gamma-glutamyl transferase (GGT), glucose, lactate dehydrogenase (LDH), magnesium, total protein and triglycerides from sitting to standing. The parameters with meaningful bias from sitting to upright were hemoglobin, hematocrit, albumin, ALP, total bilirubin, calcium, total and HDL cholesterol, glucose, LDH and total protein.
  
  
  CONCLUSIONS
  These results provide further support to the need of standardizing patient's posture during phlebotomy.
authors.affiliation: Laboratory of Clinical Chemistry and Hematology, Academic Hospital of Parma, Parma, Italy. Electronic address: glippi@ao.pr.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Lippi
authors.affiliation: Laboratory of Clinical Biochemistry, Department of Life and Reproduction Sciences, University of Verona, Verona, Italy.
authors.forename: Gian Luca
authors.initials: GL
authors.lastname: Salvagno
authors.affiliation: Laboratory of Clinical Biochemistry, Department of Life and Reproduction Sciences, University of Verona, Verona, Italy.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Lima-Oliveira
authors.affiliation: Laboratory of Clinical Biochemistry, Department of Life and Reproduction Sciences, University of Verona, Verona, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Brocco
authors.affiliation: Laboratory of Clinical Biochemistry, Department of Life and Reproduction Sciences, University of Verona, Verona, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Danese
authors.affiliation: Laboratory of Clinical Biochemistry, Department of Life and Reproduction Sciences, University of Verona, Verona, Italy.
authors.forename: Gian Cesare
authors.initials: GC
authors.lastname: Guidi
mesh_terms: D000328:Adult; D001663:Bilirubin / Q000097:blood; D001774:Blood Chemical Analysis / Q000379:methods* / Q000592:standards; D002118:Calcium / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D019963:Clinical Chemistry Tests / Q000379:methods* / Q000592:standards; D005260:Female; D006801:Humans; D008274:Magnesium / Q000097:blood; D008297:Male; D008875:Middle Aged; D018962:Phlebotomy / Q000379:methods*; D011187:Posture / Q000502:physiology*; D012709:Serum Albumin / Q000032:analysis; D016683:Supine Position; D014280:Triglycerides / Q000097:blood
chemical_list: D008076:Cholesterol, HDL; D012709:Serum Albumin; D014280:Triglycerides; D008274:Magnesium; D001663:Bilirubin; D002118:Calcium
keywords: Clinical chemistry; Laboratory testing; Plasma volume change; Posture; Preanalytical variability