Thrombin generation: a comparison of assays using platelet-poor and -rich plasma and whole blood samples from healthy controls and patients with a history of venous thromboembolism.

We have developed a whole blood thrombin generation (TG) assay whereby TG is initiated with a low-tissue factor concentration and monitored using a fluorogenic thrombin substrate. Significantly higher values were found in blood samples from 50 patients with a history of venous thromboembolism (VTE) compared with 31 healthy controls (HC), for peak height (P = 0.0034) and endogenous thrombin potential (ETP) (P = 0.0027). Results from 31 VTE patients and the 31 controls in the absence of corn trypsin inhibitor (CTI) showed significantly higher values in the VTE group for peak height (P = 0.0013) and ETP (P = 0.002). In the presence of CTI, significantly higher values were only seen in ETP (P = 0.024). No significant increases in TG were found using platelet poor (PPP) or -rich (PRP) plasma with or without CTI. The whole blood TG assay in the absence or presence of CTI showed a higher proportion (25/50 and 12/31, respectively) of raised peak height and/or ETP values than plasma assays (PPP 9/50 and 5/31 respectively and PRP 13/50 and 6/31, respectively). Our results show the whole blood TG assay is more sensitive for determining the increases in TG in patients with a history of VTE than PPP and PRP TG assays.