Platelet Function Analysis by Flowcytometry in Thrombocytopenic Trauma Patients

2020 ◽  
Author(s):  
Tapasyapreeti Mukhopadhyay ◽  
Arulselvi Subramanian ◽  
Venencia Albert ◽  
Anand Kumar ◽  
Shyam Prakash ◽  
...  
Keyword(s):  
Platelet Function ◽  
Function Analysis ◽  
Trauma Patients

Coagulation parameters and platelet function analysis in patients with acromegaly

2015 ◽  
Author(s):  
Hamiyet Yilmaz Yasar ◽  
Mustafa Demirpence ◽  
Ayfer Colak ◽  
Banu Ozturk Ceyhan ◽  
Yusuf Temel ◽  
...  
Keyword(s):  
Platelet Function ◽  
Function Analysis ◽  
Coagulation Parameters

scholarly journals A Platelet Acquired Storage Pool Disorder Associated with Tamoxifen Therapy

2012 ◽  
Vol 2012 ◽  
pp. 1-3 ◽  
Author(s):  
Lalitha Nayak ◽  
Alvin H. Schmaier
Keyword(s):  
Breast Cancer ◽  
Platelet Function ◽  
Tooth Extraction ◽  
Function Analysis ◽  
Tamoxifen Therapy ◽  
Storage Pool ◽  
Prolonged Bleeding ◽  
Platelet Storage

The antiestrogenic drug tamoxifen, used in patients with breast cancer, is associated with an increase in arterial and venous thrombotic events, the mechanism of which is not clearly understood. We report a case of a lady who presented with new bruising and prolonged bleeding following a tooth extraction 4–6 weeks after starting tamoxifen. Investigations were consistent with an acquired platelet storage pool disorder. Repeat platelet function analysis was normal, performed 3 months after discontinuation of tamoxifen. We present a previously clinically unreported effect of tamoxifen on platelet function.

Complement Activation in Trauma Patients Alters Platelet Function

Shock ◽  
2016 ◽  
Vol 46 (3S) ◽  
pp. 83-88 ◽  
Author(s):  
Gelareh Atefi ◽  
Omozuanvbo Aisiku ◽  
Nathan Shapiro ◽  
Carl Hauser ◽  
Jurandir Dalle Lucca ◽  
...  
Keyword(s):  
Platelet Function ◽  
Complement Activation ◽  
Trauma Patients

Rapid Assessment of Platelet Function Using Thromboelastography and Small Volumes of Citrated Whole Blood.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3995-3995 ◽  
Author(s):  
Fred G. Pluthero ◽  
Margaret L. Rand ◽  
Victor S. Blanchette ◽  
Walter H. Kahr
Keyword(s):  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Platelet Function ◽  
Whole Blood ◽  
Function Analysis ◽  
Maximum Amplitude ◽  
Ease Of Use ◽  
Platelet Response ◽  
Platelet Function Disorders ◽  
Wide Range

Abstract Platelet function disorders are a key cause of abnormal bleeding, and diagnosis is challenging because: platelet abnormalities are diverse, affecting many aspects of function; variability in platelet function testing in clinical laboratories makes it difficult to compare results; large blood volumes required for platelet function analysis make it difficult to perform in neonatal patients; manipulation of platelet rich plasma used for platelet aggregation can lead to test variability; platelet aggregation curves are difficult to interpret in thrombocytopenic patients. We describe a method of testing platelet function using citrated whole blood and thromboelastography (TEG) that overcomes some of these limitations. Commercially-available platelet mapping kits allow the effects of the platelet agonists adenosine diphosphate (ADP) and arachidonic acid (AA) to be assessed via a TEG assay where reptilase and activated factor XIII produce fibrin clots independent of thrombin in heparinized whole blood. The activation and aggregation of platelets is quantified by measuring the difference in maximum amplitude (MA) between unstimulated samples, which form weak fibrin-only clots, and samples with agonists added, which form stronger clots containing fibrin and activated/aggregated platelets. Platelet mapping was used as the basis for a TEG assay which can be used to assess platelet responses to a wide range of stimuli - including ADP, AA, epinephrine, collagen, U46619 (thromboxane-A2 receptor agonist), SFLLRN (PAR-1 thrombin receptor activating peptide) and AYPGKF (PAR-4 activating peptide) - in small samples (330μL) of citrated native (CN) blood or plasma to which heparin is added to a concentration of 20U/mL. Samples were recalcified by adding calcium chloride to 10mM (necessary for the function of reptilase and FXIIIa), and other reagent volumes were the same as in platelet mapping assays, with fibrin activator prepared at 1/2 regular strength. The concentrations of platelet agonists were: collagen 51μg/ml, epinephrine 0.27μM, ADP 5.4μM, arachidonic acid 135μg/mL, U46619 2.6μM, SFLLRN 6.76μM and AYPGKF 34μM. These concentrations produced TEG MA values in heparinated fibrin-activated CN blood from a panel of normal individuals comparable to those obtained from recalcified CN blood in the absence of heparin (the fibrin/platelet response control). The platelet response was rapid with maximum amplitudes reached within 10 minutes for all agonists except collagen, which required >30 minutes to produce maximum amplitude. We have found this TEG platelet-response assay to be useful in detecting platelet function abnormalities, producing results which correlate with and extend those of other platelet function tests. For example in one patient a weak response to epinephrine corresponded to similar platelet aggregation results, and in another the TEG assay detected a weak PAR-1 response not specifically detected in other tests. The assay has also proven useful in assessing platelet function in blood and plasma having low platelet concentrations (<50 x 10E9/L) from experimental or pathological causes (e.g. thrombocytopenia), in titrating platelet responses to agonists and in assessing the effects of antiplatelet agents in vivo and in vitro. Thus this TEG platelet function assay has the advantages of speed, ease of use, flexibility, adaptability to low platelet concentrations and sample economy, requiring small volumes of citrated blood which can be used for other coagulation assays and platelet response tests.

The Relationship between ABO Groups, Factor VIII, von Willebrand Factor Levels and Platelet Function Analysis Using Cone and Plate(let) Analyzer.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4024-4024
Author(s):  
Maria Lourdes Barjas Castro ◽  
Aline Crucello ◽  
Heloise P. Fernandes ◽  
Norma C. Sousa ◽  
Joyce M. Annichino-Bizzacchi ◽  
...  
Keyword(s):  
Factor Viii ◽  
Blood Group ◽  
Platelet Function ◽  
Von Willebrand Factor ◽  
Function Analysis ◽  
World Health ◽  
Enzyme Linked Immunosorbent Assay ◽  
Abo Blood Group ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract ABO blood group has been described to influence levels of von Willebrand factor (VWF), as well as factor VIII. Individuals carrying O allele have significant lower plasma levels of these factors. Indeed, recently non-O individuals have been described to have increased risk for both, arterial and venous thrombotic disease. VWF mediate platelet interaction with areas of damage blood vessel wall. Thus, it could be interesting to evaluate the possible influence of the ABO group in this interaction, particularly in situations in which low levels of VWF are close to those found in VW disease (such in O group). Cone and plate(let) analyzer (CPA) represent a simple and fast method, that allow the evaluation of platelet function (adhesion as well aggregation) in whole blood under shear conditions, closer to physiological conditions. In this method, no platelet agonists are needed and interaction with fibrinogen and VWF is particularly evaluated. The aim of the present study was to evaluate the influence of ABO group in platelet function using CPA. Samples from 15 male blood donors with no history of drug intake, were submitted to ABO serology and molecular analysis, VWF:Ag, FVIII dosages, and CPA analysis using Impact-R (Diamed - Switzerland), according to manufacturer’s instructions. ABO phenotypes were determined by agglutination test using monoclonal and polyclonal anti-A, B and AB antibodies (Asem-NPBI, São Paulo Brazil; DiaMed SA, Suisse; DiaMed Latino América, Brazil). H antigen was determined using anti-H lectin from Ulex europaeus (DiaMed Latino América, Brazil). ABO genotyping was performed by polymerase chain reaction (PCR) amplification of exons 6 and 7 of the ABO gene, followed by diagnostic restriction enzyme digestion. Factor VIII coagulant was measured by a one stage clothing method using a factor-VIII deficient substrate. VWF:Ag was measured by an enzyme linked immunosorbent assay (ELISA) using polyclonal antiserum (Dako, Denmark). Lyophilised commercial reference preparations of VWF:Ag, and FVIII, standardized against the World Health Organization standard, were used as the standards in this study. The age of the donors ranged from 27–65 years (median = 42 years). The donors were distributed according to ABO groups: 5 = OO; 5 = AB; 5 = AO. Median levels of factor VIII, according to blood group were: OO= 79% (70–142%); AO= 87% (80–140%); AB= 112% (98–200%). Median levels of VWF, according to blood group were: OO= 79% (50–99%); AO= 82% (73–120%); AB= 169% (92–250%). CPA analysis presented the following results: median AS in μm2 (average size) - OO= 24 (23–42); AO= 33 (24–42); AB= 23 (21–24) - median SC in % (surface coverage) - OO= 7.1 (4–13); AO= 8 (5–8); AB= 6.9 (4.8–8). No significant differences using Wilcoxon’s rank sum test were found among groups, when platelet function was analyzed. In conclusion, our results suggest that, although O allele carriers present lower levels of both factor VIII and VWF, the use of platelet function analysis does not seem to predict the risk for bleeding or thrombosis, according to individual ABO blood group.

Comprehensive Quality Management of Multiple Electrode Platelet Aggregometry.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4463-4463
Author(s):  
Michael Spannagl ◽  
Andrea Dick ◽  
Andreas Calatzis
Keyword(s):  
Quality Control ◽  
Quality Management ◽  
Correlation Coefficient ◽  
Platelet Function ◽  
Function Analysis ◽  
Management Approach ◽  
Platelet Function Tests ◽  
Control Material ◽  
Test Cells ◽  
Multiple Electrode

Abstract Abstract 4463 Platelet function analysis provides quantitative results which may reveal platelet disorders, platelet inhibition during anti-platelet therapy or anti-platelet drug resistance. The results may have important consequences on patients therapy. As in all laboratory methods, a comprehensive quality management approach is crucial and increasingly demanded by regulatory authorities. In platelet function methods quality control is hampered by the fact that platelets are not stable over longer time periods and loose their functional activities after freezing and freeze-drying. Therefore for most platelet function tests no control materials are available. When no biological quality control material is available, it is even more important to install and maintain a quality management approach, which covers as many influence factors and sources of error as possible. Here we present the quality management procedures of Multiple Electrode Aggregometry (MEA) a relative new platelet function test based on the analysis of whole blood (Multiplate analyzer, Dynabyte medical, Munich, Germany). In the MEA device temperature of the measurement system is controlled by the analyser and can be verified by an external QC kit. The signal reaction of this method is based on the rise of electrical resistance induced by the adhesion and aggregation of activated blood platelets on metal sensor electrodes in a disposable test cell. In order to control possible sensor inconsistencies and improve precision, the test cell incorporates two independent sensor units, each consisting of 2 silver-coated highly conductive wires. The duplicate sensors thus serve as an internal control. During each measurement Pearson's correlation coefficient of single measurements of the curves assessed by the two electrode pairs and the difference of the two AUCs are calculated automatically by the analyzer's software. The result is flagged if the values are outside of the acceptance range (correlation coefficient <0.98, difference to the mean curve >20%). The instrument has an integrated procedure for an electronic control which checks the function of the electronic amplifier in the analyzer. In addition liquid controls are available, based on solutions with different ional strength. Using these solutions the instrument, pipettor and test cells are controlled. Using blood from a healthy individual, users can control qualitatively all aspects of the analysis (instrument, test cells, reagents, pipettor). Abnormal control reagents are available, containing either aspirin, a GpIIbIIIa antagonist or prostaglandin E1, which can produce an abnormal result when added to a normal blood sample before the analysis. The instrument provides an electronic pipettor with interactive software-guided operation procedures, which help standardise the analysis and minimize user-related errors. Using artificial liquid control materials a pilot external QC was performed in 6 individual centers and the results were centrally analyzed. Level I control was determined as 125+-6 aggregation units (AU, mean+-sd), level II control was 64+-5 AU. Coefficients of variation of all determinations were 4.6% and 7.3% respectively. In conclusion it is shown that while a stable biological control material for platelet function analysis is not available, it is possible to perform quality controls covering many parts of the analytical procedure. Manufacturers and users of platelet function tests should try to implement control procedures that cover as many aspects of the technology they apply as possible to ensure correct performance of the tests over the lifetime of the instrument, test cells and reagents. As long as stable biological quality control materials for platelet function analysis are not available, qualitative biological controls using normal blood or plasma should be combined with artificial control materials or electronic test procedures according to the analytical reaction which is performed. If the biological reaction cannot be quantitatively controlled, then at least the physical process leading to the signal of the respective test procedure should be verified (measurement of pressure, optical density or electrical impedance). Using a step by step approach comprehensive quality management of platelet function analysis is feasible and should be implemented in routine. Disclosures: Calatzis: Dynabyte Medical : Equity Ownership, Patents & Royalties.

The Predictive Value of Modified Computerized Thromboelastography and Platelet Function Analysis for Postoperative Blood Loss in Routine Cardiac Surgery

2003 ◽  
Vol 96 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Ursula Cammerer ◽  
Wulf Dietrich ◽  
Tobias Rampf ◽  
Siegmund L. Braun ◽  
Josef A. Richter
Keyword(s):  
Cardiac Surgery ◽  
Blood Loss ◽  
Platelet Function ◽  
Predictive Value ◽  
Function Analysis ◽  
Postoperative Blood Loss
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