A normal range study for the T-TAS(R) with three different chips

Introduction The T-TAS®​ (Total Thrombus formation Analysis System) is a device for assessing hemostasis in whole blood under physiological flow conditions. Resembling a modified flow chamber principle, it measures the change of flow during thrombus formation within micro capillaries in disposable microchips. The global assays measure different aspects in hemostasis. We determined the normal ranges of the three available chip types for a typical European healthy population and compared the variability between labs.

Method The T-TAS®​01 (CE marked, FUJIMORI KOGYO Co.) contains an integrated pump and pressure sensor. A blood sample, applied to the respective chip, is pumped through the flow path under optimized conditions. Thrombus formation begins, when blood reaches the area, coated with either collagen only (PL-chip) or collagen plus tissue thromboplastin (AR-/ HD-chip). The pressure change inside the flow path is examined, providing the reaction kinetics of the entire thrombus formation process (pressure/time diagram). Derived results such as area under the curve (AUC) are computed. 50 samples from healthy subjects of both sexes (age range 20 to 80 y) with normal CBC, normal VWF and without any medication were enrolled per center (named as L and HH). Blood for the PL-chip (platelet function) was collected into BAPA (Benzylsulfonyl-D-Arg-Pro-4-amidinobenzylamide)- vacuum tubes. For the AR- and HD-chip (AR: platelet and coagulation interaction, HD: thrombogenicity at low platelet counts), one center (HH) collected blood in vacuum tubes (Vacutainer®​, Becton Dickinson and Co), the other (L) employed the aspiration technique (Monovette®​, Sarstedt AG & Co. KG). Samples were tested within<2 hours with the three different chip types. Statistically, Wilcoxon-Mann-Whitney test was used, considering p<0.05 as a statistically significant difference. Analyze-it®​ (Analyse-it Software, Ltd., UK) was used as a statistical analysis software.

Results The data show a very similar ranges for the PL-chip in both centers, though with a wider distribution in one center. The PL-AUC mean values (L; 352 and HH; 364) were not significantly different. The 5-95% percentiles for 99 samples for PL-AUC were 260- 424. Similarly, for the HD chip the values of the two centers were not statistically different (mean HD-AUC: 1535(L) and 1565(HH), 5-95% perc.: 1420- 1622). The AR chip values were statistically different between the two centers. AR-AUC mean values were 1262(L) and 1344(HH), 5-95% perc.: 908 – 1484 [1] [2].

Conclusion The similar ranges of results in the two centers show that the method generates reproducible data for the assessment of haemostasis. Minor differences for the AR assay are probably associated to the blood collection methods employed. These data may help other centers in interpreting own T-TAS®​ data.

Conflict of Interest

S. Schneppenheim, U. Klemm and C. Pfrepper, R.Henschler, C.Franke, K. Freitag: no conflict of interest. Ohsawa H is an employee of FUJIMORI KOGYO Co., Ltd., which is the manufacturer of the T-TAS 01. Kolde HJ is a consultant to FUJIMORI KOGYO Co. Ltd.

• References

• 1 Thromb Hemostas J. 2011; 9 (19) 2029-2037
• 2 Thromb Hemostas J. 2007; 5 (10) 2119-2126

Publication History

Article published online:
26 February 2024