PO0018 - Reference Range Determination for the Novel T-TAS 01 AR Assay

Background: The T-TAS 01 AR assay is a novel in vitro diagnostic system that measures total thrombogenicity in whole blood samples using a flow chamber model of vascular injury. Citrated whole blood is recalcified and spiked with corn trypsin inhibitor to inhibit the intrinsic coagulation pathway and passed at large vessel arterial shear rates through a thrombogenic path coated with collagen and tissue thromboplastin to produce platelet-rich thrombus formation. Flow pressure increases inside the chip proportionally as the thrombus forms and impedes flow. Results are reported as occlusion time (OT; sec), which is the time at which flow has stopped due to thrombus formation.

Aims: To establish a preliminary T-TAS 01 AR assay reference range from healthy donors and to evaluate the repeatability of the assay.

Methods: Healthy subjects were enrolled according to an IRB-approved protocol at two investigational sites. Blood samples were collected into evacuated tubes containing 3.2% sodium citrate. Subjects were screened for possible primary or secondary hemostasis defects using standard laboratory methods. T-TAS 01 AR measurements were performed between 30-120 minutes after blood collection. Reference ranges were calculated as the central 90% distribution using the quantile method and the average replicate CV was calculated from the overall mean OT and mean variance.

Results: 49 subjects who had no evidence of primary or secondary hemostasis defects were included in the analysis. The study population was 65% female, aged 20-68 years. The OT reference range was 357-729 seconds. The overall CV for the replicates was 11.9%.

Conclusion(s): The T-TAS 01 AR assay reference range in healthy donors was 357-729, and the average CV between replicates of 11.9% demonstrated good reproducibility. Establishment of the T-TAS 01 AR assay reference range will be helpful for the interpretation of results as normal or abnormal, and abnormal results can be further categorized as hyperthrombotic or hypothrombotic.