Background: Thromboelastography is a viscoelastic test of whole blood hemostasis. Currently, no reference value exists for native whole blood and recalcified citrated blood without activators. The aim of this study was to compare the results of ROTEM® tests using fresh native blood without decalcification "TRUE-NATEM" with those using decalcified citrated blood "NATEM" and provide reference values for each. Methods: Inclusion criteria were healthy adult volunteers (18-65 years). Exclusion criteria were any medical condition or medication affecting coagulation. Native whole blood testing was defined as "TRUE-NATEM-test." For recalcified citrated blood testing, the NATEM function was used on ROTEM®. Result: The reference value for TRUE-NATEM was CT: 872-1595s, A10: 14-34 mm, A20: 26-48 mm, CFT: 314-839s, MCF: 34-55 mm, and alpha angle: 17-40°. The reference value for NATEM was CT: 757-1327s, A10: 19-43 mm, A20: 33-55 mm, CFT: 219-615s, MCF: 37-61 mm, alpha angle: 24-51°, and ML: 0-3%. When comparing the reference value of NATEM to TRUE-NATEM, the CT and CFT values are decreased and the MCF and alpha angle are increased. The recalcification process of citrated blood in NATEM shows significant activation of coagulation. Female healthy volunteers had enhanced coagulation when activators were used. Age-related statistical difference was seen when activators were used. Ethnicity did not show any difference on the ROTEM values. Conclusion: We determined the reference value for native whole blood and recalcified whole blood using ROTEM®. A significant discrepancy in native whole blood and recalcified citrated blood coagulation was found. Our study underlines the importance of native whole blood as the gold standard reference value in coagulation.
Keywords: NATEM; ROTEM; TRUE-NATEM; reference value; validation.