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

Abstract

Introduction The “gold standard” diagnostic test for assessing in vitro platelet function, light transmission aggregometry (LTA), has limitations to application because of sample requirements. Whole blood or multiple electrode aggregometry (MEA) using the Multiplate® analyzer (Roche Diagnostics) requires smaller blood volumes and less sample manipulation than LTA, making it an attractive clinical testing option. Direct comparisons of MEA with LTA for diagnosis of platelet aggregation abnormalities are few. Methods Ninety‐nine patients (66 F/33 M; median age 26 [range 2‐86] years), referred for initial laboratory evaluation of mucocutaneous bleeding, had parallel MEA/LTA testing. Concentrations of ADP, arachidonic acid (AA), collagen, and thrombin receptor‐activating peptide (TRAP) that produced threshold responses in normal controls were used for testing patients. Results Twenty‐nine of the 99 patients (30%) had at least one abnormal agonist response by LTA; 15 of these patients had >1 abnormal agonist response. Thirty‐six patients (36%) had at least one abnormal agonist response by MEA; 27 had >1 abnormal agonist response. Sensitivity/specificity of MEA relative to LTA: ADP, 0.70/0.72; AA, 0.71/0.85; collagen, 0.85/0.71; TRAP 0.25/0.84. Negative predictive values (NPVs) for MEA relative to LTA: ADP, 0.90; AA, 0.93; collagen, 0.97; TRAP, 0.96. Conclusions Specific abnormal results of MEA testing did not adequately predict specific abnormalities in LTA testing using threshold agonist concentrations. However, favorable NPVs suggest that MEA may be useful in screening patients for platelet aggregation abnormalities; those with normal MEA results not requiring further diagnostic testing by LTA.

The MICELI (MICrofluidic, ELectrical, Impedance): Prototyping a Point-of-Care Impedance Platelet Aggregometer

“…Significant differences were observed between agonist doses, suggesting that the device can detect even micromolar changes in ADP and collagen concentrations in whole blood. Low-level aggregation was detected even at minimal agonist concentrations, 1 µM ADP and 1 µg/mL collagen, recommended for clinical application of EIA [35]. These experiments showed that the MICELI aggregometer could be used to evaluate different pathways of platelet activation and provide comprehensive information on platelet function and the effectiveness of antiplatelet therapy.…”

“…To test the sensitivity of the MICELI device to agonist concentrations in whole blood, platelet aggregation was induced with ADP and collagen. Threshold agonists' concentrations were chosen based on recommendations of the previous studies aimed to validate platelet aggregometry assays for clinical use [35]. The resulting curves showing a linear, dose-dependent increase of platelet aggregation with the increase of agonist concentration are reported in Figure 5.…”

Cardiopulmonary bypass‐induced coagulopathy in pediatric patients: The role of platelets in postoperative bleeding. A preliminary study

“…24 Indeed, a recent report revealed that Multiplate analysis may constitute a less reliable and reproducible tool than light transmission lumi-aggregometry for studying platelet function in pediatric patients. 25 Finally, the bleeding severity was assessed using only one definition (i.e., chest tube output).…”

The Current Role of Platelet Function Testing in Clinical Practice

“…An obvious advantage of using whole blood is the negation of need for timeintensive steps of preparing PRP and the ability to perform testing using smaller blood volumes (3 mL). 13 The OPTIMUL assay is another alternative to standard LTA, comprising a 96-well plate into which multiple platelet agonists are added individually into the plate's columns and lyophilized. Subsequent high-throughput aggregometry is performed by adding and mixing (using a specific plate shaker) patient's platelet-poor plasma (PPP) and PRP into the wells, and then recording subsequent changes in absorbance, the surrogate measure of aggregation.…”