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    Oral Communication

    Diagnostics and OMICs

    Engineering Platelets to Work for Us in Diagnosis and Treatment

    OC 23.5 - National External Quality Assessment Scheme (NEQAS BC) and Welsh Blood Service (WBS) use cold-stored platelets for External Quality Assessment (EQA) scheme for Light Transmission Aggregometry (LTA).

    Sunday, June 25, 2023
    15:45 – 16:00 ET
    Room: 710B
    Session Available As: On-Demand
    Background: Currently EQA for LTA does not audit the analytical process. NEQAS BC in conjunction with the WBS, has provided cold-stored pooled platelets for a pilot EQA exercise for LTA.

    Aims: Pooled platelets concentrates were prepared at WBS measuring between ( 833-1045 X10⁹/L) on automated cell counters. 27 sites received aliquots plus FFP in temperature regulated transport boxes, to arrive within 24 hours. Sites were required to adjust the platelet count, by diluting with FFP. LTA was performed on days 1,2 or 3 using 4 aggregation platforms.

    Methods: The platelet count at 27 sites was adjusted to 299-408 X10⁹/L prior to aggregation with agonists: ADP, arachidonic acid, collagen, epinephrine, ristocetin, TRAP and U46619. Sites were split on wether they could perform agonist concentrations of BSH or ISTH recommendations .

    Results: Table 1 includes details of agonist used, concentrations of agonists and interpretations of LTA.

    Conclusion(s): Greater than 86% consensus interpretation for results with recommended BSH or ISTH agonist concentrations, suggests platelets, delivered at 4-8°C, are a viable source of EQA material for LTA. Fifteen sites performed the testing on day 1, 8 on day 2 and 1 on day 3, (note three sites did not state testing date). The degree of interpretation consensus demonstrates that the testing time window of (1-3 days), does not affect agonist response on the aggregometer. LTA testing at multicentre locations is logistically possible. Therefore, centres can audit the majority of the analytical process, ensuring testing and interpretation is standardized when employing BSH or ISTH agonist concentrations.

    Learning Objectives:

    • To describe the process and logistics inloved to distribute fresh platelets for a possible EQA scheme to reassure clinical laboratories that the results and interpretations sre within consensus compared to other testing sites.
    • To try to encourage platelet function testing laboratories to use ISTH or BSH guidelines for agonists and the concentrations employed to investigate congenital or acquired platelet defects.
    • Highlight any potential differences in platelet aggregometers used for investigation of congential or acquired platelet defects.