The present invention relates to a method for determining a reference range of β-galactose exposure platelet in a biological sample obtained from a subject comprising the steps of: i) determining the concentration of Ricinus communis agglutin (RCA) and the value of Forward SCatter (FSC) in said biological sample; and ii) calculating the ratio between RCA and FSC.
Inventors determined an optimal RCA concentration of 12.5 µg/mL for the assay. Importantly, the measure was stable for up to 4 hours (mean fluorescence intensity (MFI)-RCA: 1233±329 at T0h and 1480±410 at T4h). The platelet count did not induce a variation of RCA and the measure of RCA was stable when tested up to 24h after blood collection, demonstrating the robustness of the assay (MFI-RCA: 17 1252±434 at day 0 and 1140±297 24 hours after blood sampling). In order to take into account the platelet size, results should be expressed as RCA/FSC ratio. They then used the assay to study variability in platelet β-galactose exposure in a population of 120 healthy adults, they found that the ratio is independent of sex and blood group and they were able to define normal range, an important step before potential widespread use of the assay.