Establishment of normal reference values for thromboelastography in Chinese elderly in Beijing

Objective To determine the normal reference values for thromboelastography (TEG) in Chinese healthy elderly people in Beijing and compare them with those provided by the manufacturer and with people under the age of 55 years. Methods The healthy elderly people aged over 65 years were enrolled from March 2014 to April 2014. 4 ml of peripheral vein blood samples were taken from each person. All subjects underwent the laboratory tests of prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT) and fibrinogen (FIB). TEG parameters including reaction time (R), coagulation time (K), angle (alpha) and maximum amplitude (MA) were determined by using a Heamoscope 5000 device. Results A total of 119 healthy elderly subjects were enrolled in this study. The mean values (95% CI) of TEG parameters for them were R: 6.29 min (4.4-8.2 min), K: 1.63 min (0.8-2.5 min), α-Angle: 66.09° (55.0-77.1°), MA: 63.43mm (54.5-72.3 mm). There were significant differences in the values of R, K and α-Angle between the elderly and non-elderly groups (P<0.001 or 0.05). There were significant differences in the values of K, α-Angle and MA between males and females (P<0.05 or 0.001). According to the normal reference values provided by the manufacturer, 16.1% (19/119) of the healthy elderly volunteers had at least one abnormal parameter beyond its normal range. 3% (3/119) of the healthy elderly people were diagnosed as coagulation abnormalities, yielding a specificity of 84%. Compared with normal reference values provided by the manufacturer, the value of R was lower and the value of MA was higher in the healthy elderly people in Beijing. Conclusions The normal reference values for TEG should be established based on the local population characteristics. Key words: Thrombelastography; Reference values