Which is the best anticoagulant for whole blood aggregometry platelet function testing? Comparison of six anticoagulants and diverse storage conditions

SummaryPlatelet function testing is essential for the diagnosis of congenital/acquired bleeding disorders and may be useful for the prediction of surgical bleeding. Nowadays there is also much interest in monitoring the efficacy of anti-platelet therapy and measuring platelet hyper-function. However, this often presents clinical laboratories with significant challenges as platelet function tests are complex, poorly standardized, time consuming and quality assurance is not straightforward. There are also few comprehensive modern guidelines available and many recent published surveys have revealed poor standardization between laboratories.Up until the late 1980’s the traditional clinical platelet function tests that were available were the bleeding time (BT), light transmission (LTA) and whole blood aggregometry (WBA) and various biochemical assays. These were also usually performed within specialized research and clinical laboratories. Since the last BCSH guidelines were published in 1988 a variety of new platelet function tests have become available. These include flow cytometry and an ever increasing choice of new commercial instruments. Although the potential clinical utility of the new assays is emerging some have not yet entered into routine clinical practice. It is encouraging that a number of standardization committees (e. g. CLSI, BCSH and ISTH Platelet Physiology SSC) are now beginning to produce new platelet function testing guidelines and this will hopefully improve clinical practice, quality assurance and result in less variability between different laboratories.

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Whole Blood Platelet Aggregometry and Platelet Function Testing

Seminars in Thrombosis and Hemostasis ◽

10.1055/s-0029-1220325 ◽

2009 ◽

Vol 35 (02) ◽

pp. 168-180 ◽

Cited By ~ 71

Author(s):

David McGlasson ◽

George Fritsma

Keyword(s):

Platelet Function ◽

Whole Blood ◽

Blood Platelet ◽

Platelet Function Testing ◽

Platelet Aggregometry ◽

Function Testing

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Flow Cytometry-Based Platelet Function Testing Is Predictive of Symptom Burden in a Cohort of Bleeders

Blood ◽

10.1182/blood.v126.23.2255.2255 ◽

2015 ◽

Vol 126 (23) ◽

pp. 2255-2255

Author(s):

Niklas Boknäs ◽

Sofia Ramström ◽

Lars Faxälv ◽

Tomas L Lindahl

Keyword(s):

Flow Cytometry ◽

Blood Flow ◽

Platelet Function ◽

Whole Blood ◽

Test Results ◽

Platelet Function Testing ◽

Fibrinogen Binding ◽

Normal Test ◽

Entire Patient Cohort ◽

Function Testing

Abstract Platelet function disorders (PFDs) are common in patients with mild bleeding disorders (MBDs), yet the clinical significance of laboratory findings suggestive of a PFD remain unclear due to the lack of evidence for a clear link between test results and patient phenotype. Herein, we present results from a study evaluating the potential utility of platelet function testing using whole-blood flow cytometry in a cohort of 105 patients undergoing investigation for MBD. Subjects were evaluated with a test panel comprising two different activation markers (fibrinogen binding and p-selectin exposure) and four physiologically relevant platelet agonists (ADP, PAR1-AP, PAR4-AP and CRP-XL). Abnormal test results were identified by comparison with reference ranges constructed from 24 healthy controls or the fifth percentile of the entire patient sample. We found that abnormal test results are predictive of bleeding symptom severity, and that the greatest predictive strength was achieved using a subset of the panel, comparing measurements of fibrinogen binding after activation with all four agonists with the fifth percentile of the patient sample (P = 0.00008, hazard ratio 8.7; 95 % CI 2.5-40). Our results suggest that whole-blood flow cytometry-based platelet function testing is a feasible alternative for the investigation of MBDs. We also show that platelet function testing using whole-blood flow cytometry could provide a clinically relevant quantitative assessment of platelet-related primary hemostasis. Figure 1. Test results for each patient in comparison with reference range (A) and the fifth percentile of the entire patient cohort (B). Normal test results are colored grey, abnormal test results are colored with a continuous color gradient using the deviation from the mean divided by the standard deviation as a measure of degree of abnormality. Grey horizontal bars illustrate the number of abnormal test results for each patient. Figure 1. Test results for each patient in comparison with reference range (A) and the fifth percentile of the entire patient cohort (B). Normal test results are colored grey, abnormal test results are colored with a continuous color gradient using the deviation from the mean divided by the standard deviation as a measure of degree of abnormality. Grey horizontal bars illustrate the number of abnormal test results for each patient. Disclosures Lindahl: Diapensia: Equity Ownership.

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Laser speckle decorrelation time-based platelet function testing in microfluidic system

Scientific Reports ◽

10.1038/s41598-019-52953-5 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Hee-Jae Jeon ◽

Muhammad Mohsin Qureshi ◽

Seung Yeob Lee ◽

Jaya Dilip Badadhe ◽

Heejoo Cho ◽

...

Keyword(s):

Platelet Aggregation ◽

Platelet Function ◽

Whole Blood ◽

Microfluidic Channel ◽

Quantitative Measure ◽

Laser Speckle ◽

Rapid Screening ◽

Contrast Imaging ◽

Platelet Function Testing ◽

Function Testing

Abstract Platelet aggregation and adhesion are critically involved in both normal hemostasis and thrombosis during vascular injury. Before any surgery, it is important to identify the number of platelets and their functionality to reduce the risk of bleeding; therefore, platelet function testing is a requirement. We introduce a novel evaluation method of assessing platelet function with laser speckle contrast imaging. The speckle decorrelation time (SDT) of the blood flowing through a microfluidic channel chip provides a quantitative measure of platelet aggregation. We compared SDTs of whole blood and platelet-poor blood, i.e., whole blood stripped of its buffy coat region, and found a marked reduction in decorrelation time for platelet-poor blood. The measured SDT of platelet-poor blood was 1.04 ± 0.21 ms, while that of whole blood was 2.64 ± 0.83 ms. To further characterize the sensitivity of our speckle decorrelation time-based platelet function testing (SDT-PFT), we added various agonists involved in platelet aggregation, including adenosine diphosphate (ADP), epinephrine (EPI), and arachidonic acid (AA). In this study, the results show that whole blood with ADP resulted in the largest SDT, followed by whole blood with AA, whole blood with EPI, whole blood without agonist, and platelet-poor blood with or without agonist. These findings show that SDT-PFT has the potential for rapid screening of bleeding disorders and monitoring of anti-platelet therapies with only a small volume of blood.

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External Quality Assessment/Proficiency Testing and Internal Quality Control for the PFA-100 and PFA-200: An Update

Seminars in Thrombosis and Hemostasis ◽

10.1055/s-0034-1365844 ◽

2014 ◽

Vol 40 (02) ◽

pp. 239-253 ◽

Cited By ~ 12

Author(s):

Emmanuel Favaloro ◽

Roslyn Bonar

Keyword(s):

Quality Control ◽

Quality Assessment ◽

Platelet Function ◽

Whole Blood ◽

External Quality Assessment ◽

Internal Quality ◽

External Quality ◽

Platelet Function Testing ◽

Primary Hemostasis ◽

Function Testing

Platelet function testing is an essential component of comprehensive hemostasis evaluation within the framework of bleeding and/or bruising investigations, and it may also be performed to evaluate antiplatelet medication effects. Globally, the platelet function analyzer (PFA)-100 (Siemens Healthcare, Marburg, Germany) is the most used primary hemostasis-screening instrument and has also been recently remodeled/upgraded to the PFA-200. The PFA-100 is sensitive to a wide range of associated disorders, including platelet function defects and von Willebrand disease (VWD), as well as to various antiplatelet medications. The PFA-100 is also useful in therapy monitoring, especially in VWD. External quality assessment (EQA) (or proficiency testing) and internal quality control (IQC) are critical to ensuring quality of test practice, inclusive of all hemostasis tests. However, both EQA and IQC for platelet function testing, including the PFA-100, is logistically challenging, given theoretical requirements for production, storage, and shipment of large volumes of “stabilized” normal and pathological blood/platelets covering both normal function plus a wide variety of potential defects. We accordingly describe the development and testing of novel feasible approaches to both EQA and IQC of PFA-100/PFA-200 instruments, whereby a range of formulated “platelet function antagonist” materials are utilized. For EQA purposes, these are distributed to participants, and citrated normal whole blood collected on site is then added locally, thereby creating test material that can be locally evaluated. Several exercises have been conducted by the Royal College of Pathologists of Australasia Quality Assurance Program (RCPAQAP) over the past 6 years. A total of 26 challenges, with most designed to mimic moderate to severe primary hemostasis defects, have been tested in 26 to 50 laboratories depending on the year of dispatch. Numerical results for PFA-100/PFA-200 closure times (CTs) and interpretive comments supplied by participants are analyzed by the RCPAQAP. During this period, reported CTs for each challenge were within limits of expectation and good reproducibility was evidenced by repeated challenges. Coefficients of variation (CVs) generated for challenges using the two major PFA-100/PFA-200 cartridge types (collagen/adenosine diphosphate and collagen/epinephrine) are always similar to those obtained using native whole blood, and in general range from 15 to 25%. Interpretations are also in general consistent with expectations and test data provided by laboratories. The EQA created material has also been assessed within the context of possible IQC material. In conclusion, EQA and IQC processes for the PFA-100/PFA-200 have been developed that include highly reproducible test challenge processes, not only supporting the concept that EQA/IQC is possible for platelet function testing but also providing a valuable mechanism for monitoring and improving laboratory performance in this area.

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