title: Interchangeability of rotational elastographic instruments and reagents.
abstract: BACKGROUND
  Viscoelastic measurements are frequently being used in clinical and research settings for a rapid assessment of the hemostatic processes of blood clot formation and degradation. These measurements are being performed on either of two instruments (TEG and ROTEM) using their proprietary reagents. Standardization between the instruments and the reagents has been lacking but is necessary to compare results across instruments. In this study, we perform a crossover analysis between the TEG and ROTEM instruments using proprietary reagents from each manufacturer.
  
  
  METHODS
  We tested three sets of reagents as follows: (1) in-tem and ex-tem (Tem International GmbH); (2) kaolin and RapidTEG (Haemonetics); (3) a well-characterized control recombinant tissue factor-phospholipid reagent. Blood was drawn from six healthy donors, and each reagent was run concurrently in the TEG and ROTEM instruments. The volume of commercial reagent and calcium used was adjusted for crossover measurements to maintain the same concentration of each reagent in the blood. The outputs of clot time, rate of clot formation, and maximum firmness of the clot of the ROTEM and the TEG tracings were evaluated.
  
  
  RESULTS
  The in-tem and RapidTEG reagents showed no disparity between instruments for any parameter. Significant differences between the instruments were found in the α angle and maximum firmness of the clot for ex-tem and kaolin reagents as well as in the clot time and maximum firmness of the clot for the recombinant tissue factor-phospholipid reagent.
  
  
  CONCLUSIONS
  Although significant differences were observed for some parameters, the magnitudes were small compared with the differences between tests or the normal range variation in parameter values observed for these tests. These findings indicate that the instruments are more interchangeable than previously reported.
authors.affiliation: From the Department of Biochemistry, University of Vermont, Colchester, Vermont.
authors.forename: Maya
authors.initials: M
authors.lastname: Aleshnick
authors.forename: Thomas
authors.initials: T
authors.lastname: Orfeo
authors.forename: Kathleen
authors.initials: K
authors.lastname: Brummel-Ziedins
authors.forename: Matthew
authors.initials: M
authors.lastname: Gissel
authors.forename: Kenneth
authors.initials: K
authors.lastname: Mann
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007202:Indicators and Reagents / Q000592:standards / Q000627:therapeutic use*; D007616:Kaolin; D008297:Male; D011994:Recombinant Proteins; D013916:Thrombelastography / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D013925:Thromboplastin; D055815:Young Adult
chemical_list: D007202:Indicators and Reagents; D011994:Recombinant Proteins; D007616:Kaolin; D013925:Thromboplastin