Comparison of multiple electrode aggregometry with lumi‐aggregometry for the diagnosis of patients with mild bleeding disorders

Abstract

Background Multiple electrode aggregometry (MEA) measures changes in electrical impedance caused by platelet aggregation in whole blood. This approach is faster, more convenient and offers the advantage over light transmission aggregometry (LTA) of assessing platelet function in whole blood and reducing preanalytical errors associated with preparation of platelet-rich plasma (PRP). Several studies indicate the utility of this method in assessing platelet inhibition in individuals taking antiplatelet agents (e.g. aspirin and clopidogrel). Objective Our current study sought to evaluate the ability of MEA in diagnosing patients with mild bleeding disorders by comparison with light transmission lumi-aggregometry (lumi-LTA). Methods Forty healthy subjects and 109 patients with a clinical diagnosis of a mild bleeding disorder were recruited into the UK Genotyping and Phenotyping of Platelets study (GAPP, ISRCTN 77951167). MEA was performed on whole blood using one or two concentrations of ADP, PAR-1 peptide, arachidonic acid and collagen. Lumi-LTA was performed in PRP using several concentrations of ADP, adrenaline, arachidonic acid, collagen, PAR-1 peptide and ristocetin. Results Of 109 patients tested, 54 (49%) patients gave abnormal responses by lumi-LTA to one or more agonists. In contrast, only 16 (15%) patients were shown to have abnormal responses to one or more agonists by MEA. Conclusions In this study we showed that MEA is less sensitive in identifying patients with abnormal platelet function relative to lumi-LTA.

Comparison of light transmission aggregometry and multiple electrode aggregometry for the evaluation of patients with mucocutaneous bleeding

“…We hypothesized that identification of threshold concentrations for agonists had the potential for improving sensitivity to mild/moderate platelet aggregation abnormalities, similar to LTA, where use of threshold concentrations is recommended . The agonist concentrations used for MEA in the present study are, therefore, lower than concentrations used in previous studies of normal controls or patients . The threshold concentrations for ADP, collagen, and TRAP used in the present study are similar to those identified by Toth et al, although the anticoagulant used for the present study was different (sodium heparin rather than citrate or hirudin).…”

“…As no patient had a confirmed diagnosis of a platelet function disorder at enrollment, the purpose of this study was not to identify the utility of either method in the identification of specific platelet function abnormalities, as described by Al Ghaithi et al . In contrast to Al Ghaithi's study, we found more patient samples with abnormal MEA responses than with abnormal LTA responses, including patients who had more than one abnormal agonist response: 28% (MEA) vs 15% (LTA).…”

“…13,14 Agonist responsiveness has been reported to differ between LTA and MEA, but direct comparison studies of the two methodologies have been few. 19,20 MEA can identify patients with severe platelet function abnormalities such as Glanzmann thrombasthenia, 20,21 but may be less sensitive than LTA to mild/moderate platelet aggregation abnormalities. 11,19,20 Most clinical studies have used the Multiplate ® manufacturer-recommended concentrations of ADP, collagen, arachidonic acid, and thrombin receptor-activating peptide (TRAP), and few studies have been done to determine optimal agonist concentrations for investigation of aggregation abnormalities.…”

High prevalence of reduced thrombin generation and/or decreased platelet response in women with unexplained heavy menstrual bleeding

“…Although LTA has shown to be useful for the detection of platelet function disorders in women with HMB, it has the disadvantage that many hospitals do not have access to a laboratory, which is using LTA. Furthermore, many laboratories have stopped using LTA, because it is time‐consuming; it requires large blood volumes to prepare platelet rich plasma and needs to be performed on freshly collected blood samples . In addition, it requires expert laboratory skills, it needs dedicated equipment, and it has a high intra‐ and interbatch and technician variability within and between tests .…”

“…Furthermore, many laboratories have stopped using LTA, because it is time‐consuming; it requires large blood volumes to prepare platelet rich plasma and needs to be performed on freshly collected blood samples . In addition, it requires expert laboratory skills, it needs dedicated equipment, and it has a high intra‐ and interbatch and technician variability within and between tests . In this study, we have used agonist‐induced platelet activation measured in whole blood .…”