Parunov LA, Surov SS, Liang Y, Lee TK, Ovanesov MV. Can the diagnostic reliability of the thrombin generation test as a global haemostasis assay be improved? The impact of calcium chloride concentration.
Haemophilia 2017;
23:466-475. [PMID:
28205396 DOI:
10.1111/hae.13174]
[Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2016] [Indexed: 11/28/2022]
Abstract
BACKGROUND
Thrombin generation test (TGT) is a global haemostasis assay with a potential to predict bleeding tendencies and treatment effects in patients with haemophilia. Despite 15 years of clinical research, the diagnostic value of TGT remains controversial, possibly due to suboptimal sensitivity to coagulation deficiencies, robustness and reproducibility.
OBJECTIVE
The goal of this study was to explore the effect of calcium chloride (CaCl2 ) concentration on the TGT's response to intrinsic coagulation factors (F) VIII, IX and XIa.
METHODS
Normal and factor-deficient plasmas supplemented with lacking coagulation factor and different CaCl2 levels were tested by calibrated thrombinography assay.
RESULTS
Thrombin peak height (TPH) was strongly CaCl2 dependent, increasing sharply from no TG at 5 mm to a peak at 13.8 mm of CaCl2 (95% confidence interval [CI]: 13.0, 14.5) in normal and normalized deficient plasmas and at 11.9 mm (CI: 9.7, 14.2) in deficient plasmas, and then decreasing slowly to a complete inhibition at 30-40 mm. In contrast, TG lag time, time to peak and endogenous thrombin potential were nearly insensitive to CaCl2 concentrations between 10 and 20 mm. The maximal difference between the TPH in deficient and supplemented plasmas was observed at 15.5 mm (CI: 12.8, 18.1).
CONCLUSION
Variations in CaCl2 concentration in the assay mixture and sodium citrate concentrations in patient plasma samples may affect TGT responses, sensitivity and result in increased inter- and intra-laboratory variance. Implementation of TGT by clinical and quality control laboratories may require optimization of CaCl2 concentration.
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