PB0124 - Establishment of reference intervals for platelet aggregation tests on new automated coagulation analyzer

Background: Implementation of platelet aggregation tests into routine practice on novel fully automated coagulation analyzer requires the establishment of agonist-specific reference intervals.

Aims: The aim of the study was to establish reference intervals for the standard panel of platelet agonists on the coagulation analyzer Sysmex CS-5100 (Siemens Healthcare Diagnostics, Germany).

Methods: Blood samples were collected into 0.109 M (3.2%) sodium citrate collection tubes (BD Vacutainer, Becton Dickinson, USA) at University Hospital Centre Zagreb during November 2023 from 52 (18 males, 34 females) healthy employee volunteers. Platelet count in platelet rich plasma (PRP) was determined on local hematology analyser Sysmex XN-550 (Kobe, Japan), showing that all samples had normal platelet values (372 ± 91×10exp9/L). Agonist induced maximal platelet aggregation was measured utilizing light transmission aggregometry in plasma samples according to manufacturer instructions. Specifically, change in optical density at 600 nm and 37 °C was measured for 600 seconds after addition of HYPHEN BioMed (Neuville sur Oise, France) agonists with following final concentrations: adenosine diphosphate (ADP, 5 µM), arachidonic acid (AA, 1 mM), collagen (2 mg/L), epinephrine (5 µM) and ristocetin (1.2 g/L). Determination of left sided reference intervals with 95% confidence intervals for each agonist was performed using MedCalc® Statistical Software version 22.013 (Ostend, Belgium) since only low values were considered suspicious.

Results: : The following agonist-specific reference intervals were obtained: >71% for 5 µM ADP (N=50), >80% for AA (N=52), >80% for 2 mg/L collagen (N=52), >73% for 5 µM epinephrine (N=51), while the obtained reference interval for ristocetin was >80% (N=52).

Conclusion(s): Considering that there are no published reference intervals for the combination of HYPHEN agonists and coagulation analyzer Sysmex CS-5100, agonist-specific reference intervals were established on our local population while utilizing the standard panel of agonists.