PB0898 - Comparative methods of platelet aggregation by light transmission in elderly patients

Background: The light transmission aggregometry of platelet-rich plasma (PRP) is considered the reference method to assess platelet function and generally it is developed in a semiautomatic aggregometer. However, it could be performed in automated optical coagulometers, allowing its execution in daily practice.

Aims: Firstly to compare platelet function methodologies between an aggregometer and an automated coagulometer using first-line agonists, evaluating the quantitative and qualitative results. Secondly to determine the minimum necessary value of PRP to achieve results within the reference interval.

Methods: Sixty-one samples from 31 non-healthy patients and 30 controls from healthy donors (obtained by venipuncture in 3.2% citrate tubes) were compared, using an Aggregometer (AggRAM) (Helena Laboratories Corporation) and a Sysmex CS-2500 (Siemens Healthineers) (Sysmex) Automated Coagulometer. PRP was prepared by centrifuging the sample for five minutes at 900 rpm. The agonists used were from Helena Laboratories for AggRAM and Hyphen Biomed for Sysmex.: 5uM Adenosine-diphosphate; 2ug/mL Collagen; 5uM Epinephrine; 1mM Arachidonic Acid; 1.5mg/mL and 0.5mg/mL Ristocetin. To ensure repeatability, a control sample was tested 6 times in one day on both instruments with each agonist. Dilutions of PRP from a healthy donor (1/2, 1/4, 1/8) were performed using PPP to evaluate the minimum value of PRP necessary for a study of platelet function. Statistic: GraphPad Instat 9 software, EP Evaluator and Microsoft Excel.

Results: With PRPs up to 150.000/mm3 platelets we obtain values within the reference interval.
Other results in attached tables.

Conclusion(s): Instruments revealed to be comparable, with good correlation and no significant statistical differences among the medians of the different agonists, showing acceptable CV%. The automatic coagulometer used on a daily basis, requires less operating time and does not demand specialized operators, making it an option to consider for the study of platelet function. The minimum quantity of platelets in PRP should be verified locally.