scholarly journals Whole blood platelet impedance aggregometry with the ROTEM platelet device: comparison of 2 anticoagulants and storage times for the establishment of canine reference intervals

2021 ◽  
pp. 104063872110513
Author(s):  
Lara M. Heimgartner ◽  
Martina Stirn ◽  
Annette P. N. Kutter ◽  
Nadja E. Sigrist ◽  
Rahel Jud Schefer
Keyword(s):  
Whole Blood ◽  
Point Of Care ◽  
Blood Platelet ◽  
Reference Intervals ◽  
Sample Storage ◽  
Rotational Thromboelastometry ◽  
Blood Samples ◽  
Impedance Aggregometry ◽  
Storage Times ◽  
And Storage

The ROTEM platelet device, a point-of-care whole blood platelet impedance aggregometer, is an add-on to the rotational thromboelastometry ROTEM delta device. The latter has been validated in dogs. We examined whether canine whole blood is suited for analysis with the ROTEM platelet device using adenosine-5′-diphosphate (ADP) and arachidonic acid (ARA) as agonists for platelet activation, and if there are significant differences between sample storage times and anticoagulants used. Subsequently, we determined canine reference intervals (RIs) for the ROTEM platelet device for ADP and ARA. In a pilot study, we examined whole blood from 7 dogs after 15-min and 60-min storage of lithium-heparinized samples and 40-min and 80-min storage of hirudinized samples. Statistical analysis showed no significant differences between ROTEM platelet device results for both ADP and ARA in lithium-heparin and hirudin anticoagulated canine whole blood. Lithium-heparinized blood samples analyzed after 15-min storage had the lowest coefficient of variation. RIs were determined for heparinized whole blood samples from 49 dogs after 15 min of storage.

scholarly journals Photoinstability of S-Nitrosothiols during Sampling of Whole Blood: A Likely Source of Error and Variability in S-Nitrosothiol Measurements

2008 ◽  
Vol 54 (5) ◽  
pp. 916-918 ◽  
Author(s):  
Yiduo Wu ◽  
Fenghua Zhang ◽  
Yang Wang ◽  
Maheshkumaar Krishnamoorthy ◽  
Prabir Roy-Chaudhury ◽  
...  
Keyword(s):  
Whole Blood ◽  
Light Exposure ◽  
Standard Addition ◽  
Aluminum Foil ◽  
Reference Intervals ◽  
Blood Samples ◽  
Butterfly Needle ◽  
Light Protection ◽  
Initial Sampling ◽  
Tube Assembly

Abstract Background: The determination of reference intervals for the concentration of total S-nitrosothiols (RSNOs) in blood is a highly controversial topic, likely because of the inherent instability of these species. Most currently available techniques to quantify RSNOs in blood require considerable sample handling and multiple pretreatment steps during which light exposure is difficult to completely eliminate. We investigated the effect of brief light exposure on the stability of RSNO species in blood during the initial sampling process. Methods: A novel amperometric RSNO sensor, based on an immobilized organoselenium catalyst at the distal tip of an electrochemical nitric oxide detector, was used to determine RSNO species in diluted whole blood without centrifugation or pretreatment. Porcine blood was collected into aluminum foil–wrapped syringes via a 12-inch butterfly needle tube assembly. Two blood samples were collected from the same animal—one with the butterfly needle tubing wrapped in aluminum foil and one with the tubing exposed to ambient room light. The RSNO concentrations in these sequential blood samples were determined by a standard addition procedure. Results: Eight sets of measurements were made in 6 animals. Samples exposed to light yielded RSNO concentrations only 23.6% (7.2%) [mean (SD)] of the RSNO concentrations determined in samples that were shielded from light and obtained from the same animals. Conclusions: These results suggest significant photoinstablity of RSNOs in whole blood and indicate the critical importance of proper light protection during sampling and processing of blood samples for the accurate determinations of endogenous RSNO concentrations.

scholarly journals Determination of Clopidogrel Resistance by Whole Blood Platelet Aggregometry and Inhibitors of the P2Y12 Receptor

2006 ◽  
Vol 52 (3) ◽  
pp. 383-388 ◽  
Author(s):  
Boris T Ivandic ◽  
Philipp Schlick ◽  
Peter Staritz ◽  
Kerstin Kurz ◽  
Hugo A Katus ◽  
...  
Keyword(s):  
Whole Blood ◽  
Adenosine Monophosphate ◽  
Blood Platelet ◽  
P2y12 Receptor ◽  
Fisher Exact Test ◽  
Exact Test ◽  
Clopidogrel Resistance ◽  
Impedance Aggregometry ◽  
Platelet Aggregometry ◽  
Increased Risk

Abstract Background: Inhibition of platelet aggregation by clopidogrel may be insufficient in up to 30% of users. These nonresponders carry an increased risk of cardiovascular events. We reported here a simple assay to study clopidogrel responsiveness. Methods: Electrical impedance aggregometry was performed in diluted whole blood in the presence of 5 and 20 μmol/L ADP. Some samples were incubated with 0.1 mmol/L methyl-S-adenosine monophosphate (MeSAMP), a P2Y12 receptor blocker, to maximize inhibition of aggregation before aggregometry. To validate the assay, we analyzed 6-min impedance in 21 healthy probands and 244 patients with coronary artery disease (CAD). Results: At 5 μmol/L ADP, the imprecision of the assay was 11%. Mean (SD) impedance of the healthy cohort was 12.2 (2.2) Ω. The mean − 3 SD was used to define the cutoff for clopidogrel responsiveness: responders and nonresponders exhibited a 6-min impedance ≤5 Ω and >5 Ω, respectively. Samples from nonresponders were incubated with MeSAMP and analyzed again to distinguish pharmacokinetic and pharmacodynamic types of resistance. Sixteen percent of CAD patients were classified as nonresponders (38 and 2 cases of pharmacokinetic and pharmacodynamic resistance, respectively). Female sex was strongly associated with clopidogrel resistance (P = 0.0002, Fisher exact test). A higher clopidogrel loading dose (P = 0.0353, Mann–Whitney U-test) was given to responders (median, 450 mg) than nonresponders (median, 300 mg). Age and cardiovascular diagnosis showed no significant associations. Conclusions: Impedance aggregometry using 5 μmol/L ADP is a useful tool for studying clopidogrel responsiveness. MeSAMP allows characterization of responsiveness “on treatment” and may be useful for optimizing clopidogrel dosing.

scholarly journals Whole Blood Immunoassay Based on Centrifugal Bead Sedimentation

2011 ◽  
Vol 57 (5) ◽  
pp. 753-761 ◽  
Author(s):  
Ulrich Y Schaff ◽  
Greg J Sommer
Keyword(s):  
Whole Blood ◽  
Single Channel ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Low Cost ◽  
Microfluidic System ◽  
Blood Samples ◽  
Reactive Protein ◽  
Immunoassay Technique ◽  
Microfluidic Immunoassay

BACKGROUND Centrifugal “lab on a disk” microfluidics is a promising avenue for developing portable, low-cost, automated immunoassays. However, the necessity of incorporating multiple wash steps results in complicated designs that increase the time and sample/reagent volumes needed to run assays and raises the probability of errors. We present proof of principle for a disk-based microfluidic immunoassay technique that processes blood samples without conventional wash steps. METHODS Microfluidic disks were fabricated from layers of patterned, double-sided tape and polymer sheets. Sample was mixed on-disk with assay capture beads and labeling antibodies. Following incubation, the assay beads were physically separated from the blood cells, plasma, and unbound label by centrifugation through a density medium. A signal-laden pellet formed at the periphery of the disk was analyzed to quantify concentration of the target analyte. RESULTS To demonstrate this technique, the inflammation biomarkers C-reactive protein and interleukin-6 were measured from spiked mouse plasma and human whole blood samples. On-disk processing (mixing, labeling, and separation) facilitated direct assays on 1-μL samples with a 15-min sample-to-answer time, <100 pmol/L limit of detection, and 10% CV. We also used a unique single-channel multiplexing technique based on the sedimentation rate of different size or density bead populations. CONCLUSIONS This portable microfluidic system is a promising method for rapid, inexpensive, and automated detection of multiple analytes directly from a drop of blood in a point-of-care setting.

MEASURING WHOLE BLOOD PLATELET AGGREGATION AND ATP-RELEASE WITH A CHRONO-LOG WHOLE BLOOD LUMI-AGGREGOMETER: EFFECT OF STORAGE TIME OF BLOOD SAMPLES

1987 ◽  
Author(s):  
F C Sieders ◽  
A C v Houwelingen ◽  
G Hornstra
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Storage Time ◽  
Bleeding Time ◽  
Atp Release ◽  
Blood Platelet ◽  
Blood Samples ◽  
Before And After ◽  
Positive Correlations ◽  
Blood Platelet Aggregation

The influence of storing blood for either one or two hours after blood sampling, on whole blood platelet aggregation and ATP-release was measured with a Chrono-log whole blood lumi-aggregometer, in 21 healthy male volunteers. Storage of blood samples, gently revolving at 37 °C in an incubator for one hour, caused a significant increase in aggregation and release as compared with results obtained immediately after sampling. After two hours' storage, the values had returned to their initial levels.Significant positive correlations were seen between values obtained before and after storage of blood, and between various aggregation and release parameters. In this study, bleeding time nor hematocrit values were significantly correlated with the aggregation and release parameters. The considerable influence of storage time on whole blood platelet aggregation and ATP-release underlines the importance of performing these determinations immediately after sampling, or possibly after a standardized storage time. Otherwise, comparison of results -obtained either in clinical situations or in trials - will increase variability as a result of which false conclusions may be obtained. This will be illustrated in a small trial using paracetamol.

scholarly journals An introduction to point-of-care testing in extracorporeal circulation and LVADs

Hematology ◽  
2018 ◽  
Vol 2018 (1) ◽  
pp. 516-521 ◽  
Author(s):  
Rachel Sara Bercovitz
Keyword(s):  
Whole Blood ◽  
Point Of Care ◽  
Blood Platelet ◽  
Ventricular Assist Devices ◽  
Bleeding Complications ◽  
Future Research ◽  
Ventricular Assist ◽  
Assist Devices ◽  
Platelet Aggregometry ◽  
Coagulation Tests

Abstract There is a delicate balance between bleeding and clotting in patients on circuits such as ventricular assist devices or extracorporeal membrane oxygenation. Traditional coagulation tests, prothrombin time, activated partial thromboplastin time, and anti-factor Xa levels, are used to monitor patients on these devices. However, turnaround times and inability to assess global hemostasis, including platelets and fibrinogen have contributed to a recognition that faster, accurate, and more informative coagulation tests are needed. Activated clotting time is used to monitor heparin in patients on circuits and has the advantages of being a near-patient point-of-care test. However, its utility is limited to heparin monitoring. Viscoelastic tests (thromboelastometry and thromboelastography) are global, whole-blood coagulation tests, and whole-blood platelet aggregometry evaluates platelet function. Ideally, these tests can ensure that patients are within the therapeutic range of their antithrombotic medications, identify patients at risk for hemorrhagic or thrombotic complications, and guide management of acute bleeding complications. This ideal is currently hampered by a lack of studies that delineate clear ranges that are clinically relevant. Future research is needed to better understand the optimal use of point-of-care coagulation testing in patients on extracorporeal circuits and ventricular assist devices.

Monitoring of Coagulation during Hemorrhagic Surgery by Central Laboratory and Near-Patient Testing. Results of a Multicenter Study.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1043-1043
Author(s):  
Pierre A. Toulon ◽  
Yves Ozier ◽  
Annick Ankri ◽  
Marie-Helene Fleron ◽  
Genevieve Leroux ◽  
...  
Keyword(s):  
Multicenter Study ◽  
Whole Blood ◽  
Capillary Tube ◽  
Point Of Care ◽  
Trauma Surgery ◽  
Control Sample ◽  
Fresh Frozen Plasma ◽  
Central Laboratory ◽  
Blood Samples ◽  
Arterial Blood

Abstract One of the critical issues in the monitoring of coagulation during surgery is the delay required to obtain results when tests are performed in a central laboratory. The CoaguChek ProDM (Roche Diagnostics) is a point-of-care (POC) coagulation analyzer designed to perform the measurement of clotting times such as the prothrombin time (PT) or the INR, and the activated partial thromboplastin time (APTT). So far, it has been mainly evaluated in the control of anticoagulation in patients on warfarin. A 45 μl-whole blood sample is disposed in the well of a specific 37°C-prewarmed single-use cartridge. It then circulates in a capillary tube coated with a specific agent. The test result is usually obtained in less than 5 min. The precision, evaluated as the “within-run” coefficient of variation (n=7), was found in the range from 3.2% to 7.3% depending of both the lyophilized whole blood control sample evaluated (normal or abnormal) and the clotting time performed. The aim of this multicenter study was to evaluate the performance of the CoaguChek ProDM in the monitoring of coagulation (PT and APTT) during hemorrhagic surgery. For that purpose, 78 patients undergoing surgical procedure (liver transplantation, liver resection, vascular and orthopedic/trauma surgery) were included in 3 centers after the study was approved by our Ethic Committee. Arterial blood samples were drawn at least 2 times: before the surgical incision and after a blood loss of 25% or more. Blood samples were simultaneously sent to the central laboratory and analyzed using the POC device. A total of 171 consecutive paired analyses were conducted. There was a very good agreement of the point-of-care-based monitoring of PT (sec) with the central laboratory monitoring (r=0.92, p<0.0001). However, the results were not identical, with significantly shorter clotting times (and lower ratios) obtained on the CoaguChek. It could be mentioned that, the difference was dramatically reduced when PT was expressed as the percentage, as it is usual in France. Comparison was less conclusive for APTT (r=0.82), with shorter clotting times (and lower ratios) again on the CoaguChek. Moreover, APTT measurement was found to be of limited interest in the studied population, particularly in the case of infusion of aprotinin which leaded to highly prolonged APTT (above the detection limits defined for the POC analyzer and for the central laboratory instrument, a STA analyzer). These results suggest that the CoaguChek ProDM allows an accurate measurement of PT in patients undergoing hemorrhagic surgical procedures. However, the results were not identical to that obtained from the central laboratory, suggesting that the transfusion algorithms would have to be adapted accordingly. One of the main advantages gained using POC testing is the ability to obtain results more rapidly. Actually, the turn-around time, defined as the elapsed time from blood sampling until availability of the results for the clinicians, was highly significantly shorter for the POC system than for the central laboratory (below 5 min vs. 60 min median value, range: 40->120 min). Finally, the clinical interest of such a point-of-care monitoring of coagulation deserves to be prospectively investigated, especially in connection with the amount of transfused fresh frozen plasma units.

Impaired ristocetin–induced Platelet Aggregation in Whole Blood Assessed with a Multiplate© Analyser Suggests a New Mechanism of Antiplatelet Effect of Aspirin and Clopidogrel,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3362-3362 ◽  
Author(s):  
Annick Ankri ◽  
Anne Baranger ◽  
Isabelle Martin-Toutain ◽  
Yves Samson ◽  
Jean-Philippe Collet ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Antiplatelet Therapy ◽  
Whole Blood ◽  
Dual Antiplatelet Therapy ◽  
Blood Platelet ◽  
Normal Control Group ◽  
Control Group ◽  
Irreversible Inhibitor ◽  
Blood Samples ◽  
Before And After

Abstract Abstract 3362 The five channel computerized Whole Blood Aggregation instrument (Multiple Platelet Function Analyzer or Multiplate®), assesses platelet aggregation based on a modified whole blood impedance aggregation method. It permits platelet aggregation to be measured after adding commonly used agonists as arachidonic acid (ASPItest), ADP (ADPtest), collagen (COLtest), ristocetin (RISTOtest) and TRAP (TRAPtest), by detecting changes in electrical resistance in whole blood. Instrument handling is easy. Results are available within 9 minutes. Our objective was to evaluate the effect of aspirin (irreversible inhibitor of COX-1) and/or clopidogrel (irreversible inhibitor of the platelet P2Y12 receptor) on whole blood platelet aggregations induced by the 5 agonists using the Multiplate® in patients treated by aspirin and/or clopidogrel. Patients and controls. Two hundred and twenty two consecutive patients were recruited: 83 treated daily by 75 or 100 mg aspirin (group A); 42 treated daily by 75 mg clopidogrel (group C); 70 treated daily by 75 or 100 mg aspirin plus 75mg clopidogrel (group AC) and 27 who were daily on 100 mg aspirin before coronary intervention were tested 12 h after dual loading dose of aspirin between 75 et 500 mg and 75 to 900 mg clopidogrel according to cardiologists' recommendations: group loading aspirin-clopidogrel (LAC). Among group AC, 23 consecutive patients requiring intracranial stent placement of supra-aortic vessel were tested first at preoperative, without antiplatelet therapy, then 1 month after initiation of daily continuous dual antiplatelet therapy by 100 mg aspirin + 75mg clopidogrel. Ninety six volunteers without pathology or drugs influencing platelet functions constitute the normal control group (N). Blood samples. All patient and controls gave informed consent prior to blood sampling. Blood samples were collected by venipuncture or obtained from the arterial sheath directly into vacutainer Becton Dickinson tube containing 0.129M sodium citrate. Results. Patients under medication showing lower aggregation values than the arbitrary cutoff (fifth percentile of the aggregation in the normal control group was selected for each agonist) were classified as abnormal and having biological sensitivity to the agonist tested. Aggregation values above the cutoff with ASPItest or ADPtest for patients on antiplatelet agents were considered as a persistent platelet aggregation and as a biological resistance. According to the literature, resistance to aspirin was found in 8.6% of patients under aspirin alone or in combination and in 25.1% of patients under clopidogrel alone or in combination. Our main result shows an inhibition in platelet aggregation using ristocetin as agonist for 73.9% of patients taking aspirin alone, for 27.8% on clopidogrel and in 94% of patients receiving combination of the 2 drugs. This inhibition appears after aspirin + clopidogrel intake as we could observe it among patients candidates for intracranial stent placement tested before and after one month of treatment by dual antiplatelet therapy. This effect is not related to von Willebrand Factor (vWF) deficiency since the measurement of ristocetin cofactor activity, and vWF antigen carried out among 14 patients exhibiting an inhibition in whole blood platelet aggregation using RISTOtest were normal and unchanged before and after antiplatelet treatment. VWF is essential platelet-to-platelet interactions which is promoted by the binding of VWF with platelet-receptor glycoprotein IbIX (GPIbIX). Our results suggest: 1) aspirin inhibits the interaction of vWF to GP IbIX. This inhibition appears increased by the association of clopidogrel to aspirin. 2) a new mechanism of inhibition of the platelet function GPIbIX-vWF dependant conjointly to inhibition of cyclooxygenase by aspirin and P2Y12 receptor by clopidogrel.Table I:Biological sensibility according to the five tests (%) in the 4 groups testedGroup (n)ASPItestADPtestCOLtestRISTOtestTRAPtestA (83)84.312.038.373.98.4C (42)38.176.219.227.816.7AC (70)90.074.348.288.222.9LAC (27)100.074.163.0100.029.6 Disclosures: No relevant conflicts of interest to declare.

Sign in / Sign up

Export Citation Format

Share Document