METHODS: A total of 120 healthy volunteers were enrolled (55 adult males, 32 adult females, and 33 children). The volunteers were interviewed for any bleeding history or drug intake which affects coagulation. Kaolin-activated TEG was performed on citrated whole blood, and parameters including R-time, K-time, angle, MA, LY30, and CI were analyzed.
RESULTS: Derived reference range for total volunteers irrespective of age and sex were as follows: R-time: 3.8-10.6, K-time: 1.2-3.1, angle: 44.9-72.0, MA: 41.2-64.5, LY30: 0-9.9, and CI: -3.7 to 3.4. Statistically significant difference was observed in different age and sex groups for R-time, K-time, and angle. About 40% of the volunteers had at least one abnormal parameter according to the manufacturer's reference range which decreased to 12.5% when the derived reference ranges were considered.
CONCLUSION: Gender- and age-related variances were observed in reference ranges of our population and which was also differed from the other ethnic population. Many of our healthy volunteers were categorized as coagulopathic when manufacturer's reference range was considered. So, it is important to derive the reference range of the target population before using the TEG into clinical practice.
METHODOLOGY: A prospective single-center cohort study was conducted in a tertiary care set-up. Transfusion Dependent Thalassemia patients registered with the pediatric unit were screened for hypercoagulability using TEG during six months of the study period and followed up for three years for the development of thromboembolic events. Patient demographics, history of splenectomy, Serum ferritin levels and annual red cell transfusion requirement (mL/kg/year) were assessed. TEG parameters used were R time, K time, alpha angle, Maximum amplitude, Clot index, and Lysis 30. The thrombin generation test (V Curve) obtained from the first-degree derivate of the TEG velocity curve was also used for analysis.
RESULTS: A total of 34 patients were recruited during the six months study period with an average age of 10.6 years ( ± 5.47). The average pre-transfusion hemoglobin level and the volume of packed red cells received were 7.24 g/dL and 152.82 mL/kg/year respectively. The TEG tracing was suggestive of a hypercoagulable state in 58.82% of patients. The mean values of angle (70.74), MA (64.16), CI (2.65) and TG (774.43) in TDT patients compared to age matched reference range (62.81, 57.99, 0.8, 577.83 respectively) was suggestive of prothrombotic changes. Annual blood transfusion requirement was negatively correlated with hypercoagulable status (-0.344, CI= -0.68 to 0.08). One out of 34 patients developed corona radiata infarct (with annual blood requirement; 112.7 mL/kg/Year). The risk to develop a hypercoagulable state appeared to be higher when the volume of RBCs transfused was less than 154 mL/kg/Year.
CONCLUSION: TDT patients are at risk of developing thromboembolism, and screening with TEG may be useful to identify those at high risk.