Thrombocytopenia affects plasmatic coagulation as measured by thrombelastography.

Thrombelastography (TEG) is used as a point-of-care test of hemostasis. Different components of the test tracing are considered to reflect various parts of the hemostatic system and to distinguish low platelet count, platelet dysfunction or both from lack of plasmatic coagulation factors. To analyze the influence of one single element of the coagulation system, namely the platelet count, we used TEG serially in patients with well documented transient thrombocytopenia. A total of 189 TEG analyses were performed from 16 patients with a hematological malignancy in remission, receiving consolidation courses of chemotherapy. TEG outcomes using unmanipulated and citrated blood samples at a median of 11 times (range 1-17) in the same patients during the decrease of platelet count in response to chemotherapy were compared with outcomes in 120 healthy adults from various age categories. We found a correlation (r = 0.7, P < 0.001) between TEG clot strength (maximum amplitude) and platelet count. Moreover, platelet count was correlated respectively with the initial rate of clot formation (reaction time and clotting time), the rate of clot growth (alpha angle), and also with maximum thrombus generation, time to maximum thrombus generation and total thrombus generation. We conclude that platelet count not only affects the strength of clot formation, as was expected, but also all other phases of plasmatic coagulation. Citration of the blood sample, aiming at easy storage of the material, masked some of the important biological parameters of coagulation.