2026 Guidelines of the Polish Society ofLaboratory Diagnostics Working Groupon Hemostasis Diagnostics for theassessment of platelet parameters andthe verification of thrombocytopenia inautomated blood counts

<ns3:p>The aim of this paper is to update and expand previously published guidelines in “Diagnostyka Laboratoryjna” by summarising contemporary methods for platelet count (PLT) measurement and platelet morphology assessment, including impedance, optical, fluorescent, hybrid, and digital technologies. The document discusses analytical artefacts (including EDTA-dependent pseudothrombocytopenia) and key pre-analytical factors, compares reference intervals (RI) for the Polish population and selected countries with attention to paediatric and geriatric subgroups and sex, and proposes a practical algorithm for verification of thrombocytopenia supported by digital image analysis. The scoping review covered publications from 2000–2026 retrieved from PubMed, Google Scholar, SciSpace, Web of Science, Scopus, and the "Diagnostyka Laboratoryjna" archive, prioritising validation studies of PLT-F/PLT-O/PLT-H, evidence on immature platelet fraction (IPF), and studies evaluating digital morphology systems (e.g., DI-60, MC-80/MC-100i). Overall, fluorescent methods (PLT-F) show the highest agreement with reference procedures in low PLT ranges. Implementation of reflex rules combining alternative measurement principles, smear review (manual or digital), and anticoagulant change (e.g., MgSO₄/CTAD) in suspected EDTA-PTCP reduces the risk of reporting erroneous results. Reference intervals in Poland for adults are 150-400 × 10⁹/L; paediatric and geriatric data confirm dependencies on age and sex. Digital image analysis increases the detection of platelet clumps, standardises smear review, and shortens turnaround time (TAT). The implementation of reflex rules based on PLT-F/PLT-O/PLT-H and digital smear assessment limits the risk of errors. Interpretation of results should consider age, sex, and population; digital morphology (DI-60, MC-80/MC-100i) should be an integral part of the verification pathway.</ns3:p>