Comparative Analysis of Thrombin Calibration Algorithms and Correction for Thrombin-α2macroglobulin Activity

Area of Science:

• Biochemistry
• Hematology
• Clinical Chemistry

Background:

• Thrombin generation (TG) testing assesses global hemostasis.
• Potential sources of variance include fluorescence artifacts like thrombin-α2macroglobulin (T-α2MG) signal, inner filter effect (IFE), and calibration algorithms.
• These variances may limit the clinical utility of TG assays.

Purpose of the Study:

• To evaluate the impact of internal versus external normalization, IFE, and T-α2MG on TG curves.
• To assess different calibration methods and their effect on TG assay robustness and accuracy.

Main Methods:

• Utilized Calibrated Automated Thrombinography (CAT) with normal plasma supplemented with coagulation factors, thrombomodulin, and tissue factor.
• Employed in-house software for analysis, comparing internal and external calibration strategies.
• Investigated the influence of T-α2MG correction and IFE on TG parameters.

Main Results:

• Various calibration methods showed no significant difference in producing TG curves or improving assay robustness.
• Thrombin peak height (TPH) from internal linear calibration did not significantly differ from uncalibrated parameters.
• TPH values from internal and external calibrations correlated well, even with T-α2MG correction.
• Higher coefficients of variation (CVs) for TPH were noted in plasma with added thrombomodulin.

Conclusions:

• Minimal differences exist between computational approaches for calibrating and correcting fluorescence signals in TG assays.
• Most samples produced similar or equivalent thrombin peak height (TPH) results across different calibration methods.
• These findings suggest that current calibration and correction strategies are largely comparable in their impact on TG results.