Caution in the interpretation of continuous thrombin generation assays: a rebuttal

Hemker, H.C.; Smedt, Erik De

doi:10.1111/j.1538-7836.2007.02513.x

Cited by 9 publications

(6 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Otherwise identical conditions run in the presence or absence of the synthetic thrombin substrate show essentially the same FG and FL response over a broad range of TF concentrations. Our findings, in addition to Hemker and de Smedt's 2007 study using a range of Z-GGR-AMC concentrations(31), show that the effect of the presence of this thrombin substrate on TG, FG, and FL responses is minimal. tPA also cleaves Z-GGR-AMC, but its concentration can be optimized so it does not affect TG while inducing a meaningful level of FL.While the experiments in this paper are potentially limited because they cover one means of TG activation in two plasmas (normal pooled or Factor IX-deficient), our present study suggests that under some conditions, a single parameter derived from either TG, FG or, possibly, FL assay may serve as predictive readout of a global hemostasis assay.…”

supporting

confidence: 72%

Interconnectedness of global hemostasis assay parameters in simultaneously evaluated thrombin generation, fibrin generation and clot lysis in normal plasma

Xin

Chang

Ovanesov

2016

Thrombosis Research

View full text Add to dashboard Cite

show abstract

supporting

confidence: 72%

Interconnectedness of global hemostasis assay parameters in simultaneously evaluated thrombin generation, fibrin generation and clot lysis in normal plasma

Xin

Chang

Ovanesov

2016

Thrombosis Research

View full text Add to dashboard Cite

show abstract

“…It has been suggested thatthe presenceofthe artificial thrombin-substrate might interferew ith the thrombin generation mechanism becauseitactsasacompetitive thrombin inhibitor (30,3 1). Hemker et al (32) have shown, however, thatt his influence is restricted to aslowingdownofthrombin inhibition by the plasma serpins and thatthe extent of this effect can be accuratelycalculated and thus compensated for (32).…”

Section: Discussionmentioning

confidence: 99%

Influence of coagulation factors and tissue factor concentration on the thrombin generation test in plasma

Duchemin¹,

Pan‐Petesch²,

Arnaud³

et al. 2008

Thromb Haemost

102

View full text Add to dashboard Cite

The thrombin generation test is used to study coagulation in patients with haemorrhagic diseases or with high thrombotic risk. To our knowledge, this is the first study investigating the relative influence of coagulation factors on thrombin generation in plasma. The aim was to investigate the influence of coagulant factors, anticoagulant factors, and tissue factor (TF) on three parameters: endogenous thrombin potential (ETP), peak thrombin concentration, and lag time for the appearance of thrombin. At a low TF concentration, all factors except factor XI influenced thrombin generation. At a high TF concentration, only the factors of the extrinsic pathway exerted an influence. ETP and peak thrombin were linearly correlated to factor II concentration. Factor V and factor VII effects increased hyperbolically with factor concentration. The influence of factor X on thrombin generation depended on TF concentration. In the absence of factor VIII and factor IX, ETP fell to 60-70% of the normal when peak thrombin fell to 25-30% of the normal. Fibrinogen concentration influenced ETP and peak thrombin and decreasing fibrinogen levels shortened the lag time. As expected, decreasing antithrombin concentration caused dramatic increases in thrombin generation. Protein S prolonged the lag time, especially at a low TF concentration. No effect of protein C was observed, likely due to the absence of thrombomodulin. The thrombin generation test was more sensitive to factor deficiencies at low than at high TF concentration. ETP was not the most critical parameter for studying coagulation factor deficiencies. Instead, peak thrombin was the most sensitive parameter.

show abstract

“…The absolute valueso ft he different parameterss hown in Table3cannot be compared directly betweenmethods Aand B because the reaction mixturesare differentastotissue factor and phospholipid content, Ca ++ -concentration,p lasma-dilution and substrateconcentration (22).The high valuesfor the ETP seen with method Amight seem to be in contradiction with the low peak and slope valuesb ut aree xplained by the fact thatt he α2M-thrombin component to the ETP is not subtracted (see above).…”

Section: Experimental Accuracymentioning

confidence: 99%

The technique of measuring thrombin generation with fluorogenic substrates: 1. Necessity of adequate calibration

Smedt¹,

Dieri²,

Spronk³

et al. 2008

Thromb Haemost

View full text Add to dashboard Cite

In fluorogenic thrombin generation (TG) measurement the concentrations of thrombin are obtained from the course of fluorescence intensity. Because of fluorescence quenching, in one series of normal plasmas (n = 60), the rate of fluorescence increase at fixed thrombin activity was 70 +/- 13% of that in buffer, in another (n = 139) 75 +/- 8%. Using a calibration factor (CF) measured in buffer therefore underestimates thrombin concentrations in plasma and introduces a source of error. A fixed CF also neglects the 25-35% increase of CF during the experiment and thus distorts the form of the TG curve so that the ETP cannot be determined. Continuous individual calibration (CIC), in which CF is determined continuously in a parallel sample, avoids such systematic errors but adds random error because the thrombin course is calculated from two different measurements. We determined the intra-individual coefficients of variation (CV) of the peak-height and ETP as obtained with CIC to those obtained with a fixed CF measured in buffer. With the fixed CF, the CVs varied between 18% and 49%; with CIC they lowered to 4-7% (n = 5 x 12), i.e. in a range allowing clinical application. It is shown that CIC can be discarded for the measurement of peak thrombin values and replaced by comparison to a reference plasma only if quenching is not a systematic confounder. This was shown to be the case in the set of 139 normal plasmas but not in the set used for determining the intraindividual CVs, a difference that may depend upon preanalytical conditions.

show abstract

Caution in the interpretation of continuous thrombin generation assays: a rebuttal

Cited by 9 publications

References 5 publications

Interconnectedness of global hemostasis assay parameters in simultaneously evaluated thrombin generation, fibrin generation and clot lysis in normal plasma

Interconnectedness of global hemostasis assay parameters in simultaneously evaluated thrombin generation, fibrin generation and clot lysis in normal plasma

Influence of coagulation factors and tissue factor concentration on the thrombin generation test in plasma

The technique of measuring thrombin generation with fluorogenic substrates: 1. Necessity of adequate calibration

Contact Info

Product

Resources

About