title: Different heparin lots: Does it matter?
abstract: OBJECTIVE
  To assess the impact of heparin lot on the correlation between heparin concentration and activated partial thromboplastin time (aPTT), the aPTT therapeutic range, and the heparin level.
  
  
  METHODS
  Retrospective analysis of data from 2 previous studies.
  
  
  METHODS
  Teaching institution with 929 beds.
  
  
  METHODS
  Ninety-five patients receiving heparin with 5 different lots (study 1) and 35 patients receiving heparin with 3 different lots (study 2).
  
  
  METHODS
  Laboratory-based aPTT and heparin level by anti-factor Xa analysis. Standard heparin curves were created for each lot. Each patient's heparin level was determined off each standard curve.
  
  
  RESULTS
  Correlations between heparin concentration and aPTT ranged from 0.87 to 0.89 (study 1) and 0.86 to 0.87 (study 2). Slopes of regression lines were not significantly different. Therapeutic ranges generated from lot-specific heparin levels were similar. Average bias in heparin levels from varying lots ranged from 0.005 to 0.036 units/mL.
  
  
  CONCLUSIONS
  The recommendation to reevaluate the aPTT therapeutic range with each new lot of heparin requires further evaluation.
authors.affiliation: Department of Pharmaceutical Services, William Beaumont Hospital, 3601 W 13 Mile Rd, Royal Oak, MI 48073, USA. msmythe@beaumont.edu
authors.forename: M A
authors.initials: MA
authors.lastname: Smythe
authors.forename: J M
authors.initials: JM
authors.lastname: Koerber
authors.forename: S J
authors.initials: SJ
authors.lastname: Westley
authors.forename: M
authors.initials: M
authors.lastname: Balasubramaniam
authors.forename: J C
authors.initials: JC
authors.lastname: Mattson
mesh_terms: D000704:Analysis of Variance; D006493:Heparin / Q000008:administration & dosage / Q000097:blood* / Q000592:standards*; D006801:Humans; D010314:Partial Thromboplastin Time; D011786:Quality Control; D012044:Regression Analysis; D012189:Retrospective Studies
chemical_list: D006493:Heparin