text: Investigation of the effect of kaolin and tissue-factor-activated citrated whole blood, on clot-forming variables, as evaluated by thromboelastography.
  BACKGROUND:
  The Thrombelastograph (TEG; Haemoscope Corp.) analyzes clot formation in whole blood (WB) and treatment based on this analysis has been shown to reduce transfusion requirements in liver and cardiac surgery when compared to conventional coagulation analysis. Implementing TEG as a routine laboratory-based analysis, however, requires validation of the activators employed and the effect of storage of the WB sample in citrate before analysis.
  STUDY DESIGN AND METHODS:
  The effect of kaolin, tissue factor (TF) 1:17,000, or TF 1:42,500 on TEG clotting time (R), Angle (velocity of clot formation), and maximum clot strength (amplitude [MA]) were evaluated, together with day-to-day variation, the coefficient of variance (CV%), and the effect of citrate storage time.
  RESULTS:
  Clot formation variables were equally affected by TF 1:17,000 and kaolin activation, whereas R was significantly longer when TF 1:42,500 was used. The CV for the different variables varied from 3 to 13 percent with no significant differences between assays. Storage of citrated WB significantly affected the TEG variables in a hypercoagulable direction. Only the R, however, was significantly affected (12%) when samples rested for 0 and 30 minutes were evaluated with kaolin as the activator.
  CONCLUSION:
  The TEG assays evaluated were reproducible and present with an acceptable CV% for routine clinical practice. Kaolin and TF 1:17,000 equally affected the clot formation variables. Storage of WB for up to 30 minutes in citrate did not, except for R, affect clot formation variables when kaolin was used as activator allowing for immediate analysis when the sample arrives in the laboratory.
  
entities.text: ['tissue']
entities.type: Tissue
entities.entity_id: PMID-18657078_T1
entities.text: ['whole blood']
entities.type: Organism_substance
entities.entity_id: PMID-18657078_T2
entities.text: ['clot']
entities.type: Organism_substance
entities.entity_id: PMID-18657078_T3
entities.text: ['clot']
entities.type: Organism_substance
entities.entity_id: PMID-18657078_T4
entities.text: ['whole blood']
entities.type: Organism_substance
entities.entity_id: PMID-18657078_T5
entities.text: ['WB']
entities.type: Organism_substance
entities.entity_id: PMID-18657078_T6
entities.text: ['liver']
entities.type: Organ
entities.entity_id: PMID-18657078_T7
entities.text: ['cardiac']
entities.type: Organ
entities.entity_id: PMID-18657078_T8
entities.text: ['WB']
entities.type: Organism_substance
entities.entity_id: PMID-18657078_T9
entities.text: ['clot']
entities.type: Organism_substance
entities.entity_id: PMID-18657078_T10
entities.text: ['clot']
entities.type: Organism_substance
entities.entity_id: PMID-18657078_T11
entities.text: ['Clot']
entities.type: Organism_substance
entities.entity_id: PMID-18657078_T12
entities.text: ['WB']
entities.type: Organism_substance
entities.entity_id: PMID-18657078_T13
entities.text: ['clot']
entities.type: Organism_substance
entities.entity_id: PMID-18657078_T14
entities.text: ['WB']
entities.type: Organism_substance
entities.entity_id: PMID-18657078_T15
entities.text: ['clot']
entities.type: Organism_substance
entities.entity_id: PMID-18657078_T16
entities.text: ['tissue']
entities.type: Tissue
entities.entity_id: PMID-18657078_T17