The First Case of Congenital Prekallikrein Deficiency in Korea With a Novel Pathogenic Variant (c.1198G>T)

No abstract available.

Benefits of Thromboelastography and Thrombin Generation Assay for Bleeding Prediction in Patients With Thrombocytopenia or Hematologic Malignancies

BACKGROUND: Thromboelastography (TEG) provides comprehensive information on the whole blood clot formation phases, whereas thrombin generation assay (TGA) reveals the endogenous thrombin levels in plasma. We investigated the potential significance of TEG and TGA parameters for prediction of clinical bleeding in hematologic patients on the basis of the patient's platelet levels. METHODS: TEG and TGA were performed in 126 patients with thrombocytopenia or hematologic malignancies. The bleeding tendencies were stratified on the basis of the World Health Organization bleeding grade. RESULTS: Maximum amplitude (MA) and clot formation in TEG and endogenous thrombin potential (ETP) in TGA showed significant associations with high bleeding grades (P=0.001 and P=0.011, respectively). In patients with platelet counts ≤10×10⁹/L, low MA values were strongly associated with a high bleeding risk. For bleeding prediction, the area under the curve (AUC) of MA (0.857) and ETP (0.809) in patients with severe thrombocytopenia tended to be higher than that of platelets (0.740) in all patients. Patients with platelet counts ≤10×10⁹/L displayed the highest AUC of the combined MA and ETP (0.929). CONCLUSIONS: Both TEG and TGA were considered to be good predictors of clinical bleeding in patients with severe thrombocytopenia. Combination of the ETP and MA values resulted in a more sensitive bleeding risk prediction in those with severe thrombocytopenia.

Performance of Four Anti-Heparin/Platelet Factor 4 Immunoassays for the Diagnosis of Heparin-Induced Thrombocytopenia

BACKGROUND: Heparin-induced thrombocytopenia (HIT) is a significant complication of heparin therapy induced by antibodies to heparin/platelet factor 4 (PF4) complexes. We investigated the diagnostic performance of four commercial immunoassays that detect the anti-heparin/PF4 antibody. METHODS: Four different anti-heparin/PF4 antibody assays were performed in 39 patients with suspected HIT: HemosIL AcuStar HIT-IgG, HemosIL AcuStar HIT-total antibody (Ab) (Instrumentation Laboratory, USA), STic Expert HIT (Diagnostica Stago, France), and PF4 Enhanced (Immucor GTI Diagnostics, USA). Patients were diagnosed with HIT when the Chong score was > or =5. RESULTS: The estimated sensitivity and specificity for diagnosis of HIT were 33.3% and 80.0% for AcuStar HIT-IgG, 55.6% and 53.3% for AcuStar HIT-total Ab, 100.0% and 37.9% for STic Expert HIT, and 33.3% and 66.7% for PF4 Enhanced. All specificities significantly increased when 4Ts scores were included in the diagnosis. The areas under the curves (AUCs) for predicting thrombosis in the AcuStar HIT-IgG, AcuStar HIT-total Ab, and PF4 Enhanced assays were 0.639, 0.522, and 0.681, respectively. When the results of each assay were analysed along with 4Ts scores, the AUC increased to 0.927 in the AcuStar HIT-IgG assay and 0.944 in the AcuStar HIT-total Ab and PF4 Enhanced assays. CONCLUSIONS: The STic Expert HIT assay had high sensitivity but low specificity for diagnosis of HIT. The performances of the three other immunoassays were comparable to each other. Specificity significantly increased when assay data were combined with 4Ts scores. Differences in the diagnostic performance of the four immunoassays were not evident, and simultaneous consideration of clinical scoring systems improved performance.

Activation of the Intrinsic Coagulation Pathway in Patients With Chronic Urticaria

PURPOSE: Although coagulation activation has been reported in chronic urticaria, data pertaining to detailed changes in coagulation factors and global coagulation status are lacking. The current study evaluated global coagulation status in patients with chronic urticaria using thrombin generation assay (TGA) and the levels of individual coagulation factors. METHODS: Patients with chronic urticaria (n=57) and 20 healthy controls were enrolled. TGA was performed under stimulation with 2 concentrations of tissue factor (TF). Coagulation factors and conventional coagulation assays were also analyzed. RESULTS: Although patients with chronic urticaria showed prolonged activated partial thromboplastin time, prothrombin time did not differ significantly between patients and controls. In both 1 pM and 5 pM TF-stimulated TGA, peak thrombin and endogenous thrombin potential (ETP) levels were markedly decreased in patients with chronic urticaria. As expected, intrinsic coagulation factors (VIII, IX, and XII), as well as coagulation factors of the common pathway (II, V, and X), were consistently decreased. Additionally, D-dimer was significantly increased in patients as compared to controls. In multivariate regression analysis, the presence of chronic urticaria was the only significant independent contributor to the low ETP value. CONCLUSIONS: Chronic urticaria is characterized by in vivo coagulation activation through the intrinsic coagulation pathway, which can be measured with sensitivity using TGA.