BACKGROUND

Several diagnostic devices have been developed to evaluate platelet function and primary hemostasis. For example, light transmission aggregometry is known to be the gold standard in this field. However, this method requires the preparation of platelet poor plasma and is quite laborious. In addition, it has been reported that under physiological conditions, thrombus formation takes place under physiological laminar shear forces that vary strongly depending on the diameter of the blood vessel.

WHAT is the PL Chip?

The PL Chip for T-TAS^®01 is the first ex-vivo flow chamber model of in-vivo primary hemostasis available for clinical use.

PL chip technology uses physiological arterial shear stress to assess platelet thrombus formation (primary hemostasis) in whole blood. The PL chip is a flow chamber with 26 collagen-coated microcapillaries arranged in parallel. Results are generated within 40 minutes of sample collection, and 2 blood samples can be run on each PL chip. 

HOW does it work?

The test uses BAPA-anticoagulated whole blood specimens to measure platelet adhesion to a thrombogenic collagen-coated surface and platelet aggregation, which causes an increase in flow pressure inside the PL chip. The PL assay is a semi-quantitative test, but results are interpreted qualitatively based on a cutoff. The test measures primary hemostatic function as the area under the pressure-time curve (AUC). An AUC< 260 suggests abnormal primary hemostatic function. 

SPECIFICATIONS

The reportable range for the T-TAS^®01 PL assay AUC is 0.3 – 467.7.  The reportable range is established from the lowest to the highest value recorded in the clinical studies.

Precision: CV ≤ 15% or SD ≤ 39

Reference Interval: 270.0 – 447.7 AUC

(Healthy donors with no evidence of primary hemostatic abnormalities) 

PERFORMANCE

The T-TAS^®01 PL chip is intended for use in the clinical laboratory for the analysis of the platelet thrombus formation process (primary hemostatic function) in patients age 21 and older with a history of conditions associated with impaired primary hemostatic function or use of antiplatelet therapy. The test uses BAPA-anticoagulated whole blood specimens to measure platelet adhesion to a thrombogenic collagen-coated surface and aggregation, which causes an increase in flow pressure inside the PL chip. The test measures primary hemostatic function as the area under the pressure-time curve (AUC), with AUC < 260 suggesting abnormal primary hemostatic function. Additional testing may be necessary to identify the cause(s) of abnormal primary hemostatic function. The test has been evaluated in patients taking antiplatelet therapy, in patients with von Willebrand disease, and in patients with Glanzmann’s thrombasthenia. Other primary hemostasis disorders have not been evaluated. 

AUC ≥ 260 indicates that primary hemostatic defects are not identified.

AUC < 260 is considered abnormal and indicates impaired primary hemostatic function (reduced platelet thrombus formation).

Performance in VWD Patients

Von Willebrand disease severity can be highly variable, particularly in Type 1 vWD, and patients with mild vWD may not present with clinically significant bleeding.

Within the vWD patient group, abnormal PFA-100 Col/EPI and Col/ADP demonstrated sensitivity that was similar to the PL assay Col/EPI and Col/ADP demonstrated sensitivity that was similar to the PL assay (80%, [95% CI 61-90%]) and there was excellent overall agreement between the PL assay and PFA-100 assay (overall 88% [69-97%], percent positive agreement 72% [51-88%], percent negative agreement 100% [40-100%]).

All 7 of the vWD patients with PL AUC results above 260 had either normal PFA-100 results or vWF antigen, vWF activity, and FVIII:C results that were all higher than levels considered to be strongly associated with vWD (30%)

Sample Type

BAPA-anticoagulated whole blood

Sample Volume

320 μL

Test Duration

≤ 10 minutes

Sample Stability

Up to 6 hours

Reagent Storage

PL Chip: 2-8 °C

Open Pouch Stability

Up to 8 hours

Quality Control

Internal QC

External QC

(donor blood samples)

Dimensions

(W x H x D) 320 x 247 x 360 mm

Weight

6.0 kg

Operating Conditions

Temperature: 20-30 °C

Relative Humidity: 20-80%

ITEM

  REF

T-TAS^®01 Total Thrombus formation Analysis System Instrument

  18001

PL Chip for T-TAS^®01 (20 Chips)

  18002

PL Chip Reservoir Set for T-TAS^®01 (100 sets)

  18003

BAPA Tube for T-TAS^®01 (50 tubes)

  18004

IMPORTANT NOTES

The T-TAS^®01 PL chip is intended for use in the clinical laboratory for the analysis of the platelet thrombus formation process (primary hemostatic function) in patients age 21 and older with a history of conditions associated with impaired primary hemostatic function or use of antiplatelet therapy.

Physicians should use their clinical judgment and experience when deciding how to diagnose and treat patients and in the use of the PL Chip for T-TAS^®01 in the treatment of the patient. Please refer to the PL Chip for T-TAS^®01 Package Insert and T-TAS^®01 User’s Manual for full instructions on sample collection and handling, and all other test procedures.