[PLATELETS FUNCTION IN A DROP OF BLOOD: FLOW CYTOMETRY ANALYSIS COMPARED TO PLATELET AGGREGATION].

Area of Science:

• Hematology
• Clinical Diagnostics
• Pharmacology

Background:

• Light transmission aggregometry (LTA) is the standard for diagnosing platelet function disorders but has limitations.
• LTA requires substantial blood volumes and a normal platelet count, restricting its use in certain patient populations.

Purpose of the Study:

• To compare flow cytometric (FC) platelet function testing with LTA.
• To evaluate FC in diverse groups: general population, patients on anti-platelet drugs, and neonates (term and preterm).

Main Methods:

• Platelet function assessed using LTA and FC with PAC1 binding and p-selectin expression as activation markers.
• Comparison in a patient receiving Clopidogrel (before and after loading).
• Analysis of platelet activation markers in term and preterm neonatal cord blood.

Main Results:

• ADP-induced platelet aggregation correlated with FC-assayed p-selectin expression (r=0.79-0.86).
• Both LTA and FC demonstrated Clopidogrel response at 72 hours, but not 24 hours post-loading.
• Preterm neonates showed reduced ADP-induced platelet activation (p-selectin reached significance).

Conclusions:

• FC analysis of platelet function is valuable for diagnosing impaired function and anti-platelet drug response.
• FC allows testing with minimal blood volume and independent of platelet count.
• Identifying specific activation markers for each agonist is crucial for FC analysis.