title: A modified thrombin clotting time test as a quality control marker for heparin contamination in obstetric intraoperative cell salvage.
abstract: OBJECTIVE
  To assess if a modified thrombin clotting time test could be used as a simple quality control (QC) method to screen for unfractionated heparin in the product obtained from obstetric intraoperative cell salvage cases before re-infusion.
  
  
  BACKGROUND
  A national QC scheme has recently been piloted to monitor the quality of autologous blood being returned to the patient. Laboratory tests include full blood count and microalbumin. Unfractionated heparin testing should be performed to ensure that there is no gross contamination of heparin in the final product; however, presently, there is no quick cheap test available suitable for heparin detection.
  
  
  METHODS
  Samples were collected into plain non-anticoagulated tubes and centrifuged at 2500 × g for 5 min. Supernatant was mixed with commercially available coagulated normal plasma and a thrombin clotting time test performed.
  
  
  RESULTS
  Calibration runs demonstrated that our system was sensitive up to 0 · 14 IU mL(-1) heparin, linear between 0 · 08 and 0 · 14 IU mL(-1).
  
  
  CONCLUSIONS
  We have shown that the thrombin clotting time test can be modified and used as a cheap and reliable marker for heparin contamination. We have successfully incorporated this modified test into our hospital's obstetric QC scheme.
authors.affiliation: Blood Transfusion Laboratory, Royal Cornwall Hospital Trust, Truro, Cornwall, UK. ian.sullivan@rcht.cornwall.nhs.uk
authors.forename: I J
authors.initials: IJ
authors.lastname: Sullivan
authors.forename: M K
authors.initials: MK
authors.lastname: Hicks
authors.forename: J N
authors.initials: JN
authors.lastname: Faulds
authors.forename: P J
authors.initials: PJ
authors.lastname: Carson
authors.forename: R S
authors.initials: RS
authors.lastname: Noble
mesh_terms: D000328:Adult; D000925:Anticoagulants / Q000494:pharmacology*; D016063:Blood Loss, Surgical / Q000517:prevention & control; D002138:Calibration; D005260:Female; D006493:Heparin / Q000494:pharmacology*; D006801:Humans; D007432:Intraoperative Period; D013513:Obstetric Surgical Procedures; D011786:Quality Control; D013918:Thrombin Time / Q000379:methods* / Q000592:standards*
chemical_list: D000925:Anticoagulants; D006493:Heparin