The Platelet Aggregation Score and Its Correlation to β- Thromboglobulin and Platelet Factor 4 Levels

Abstract

We describe a new method of interpreting platelet aggregometry results and its correlation to platelet secretory protein levels. We studied 123 healthy male volunteers, 37-85 years of age. The aggregation response to 2.5 μM ADP was measured in a standardized platelet suspension (SPS) prepared from platelet-rich plasma. Turbidimetic measurements included amplitude of the primary aggregation wave (Amp₁), maximum aggregation amplitude (A_max), and area under the aggregation curve (S_agg). A platelet aggregation (PA) score was calculated as (Amp ₁ /A _max) ·S_agg ·(whole-blood platelet count/SPS platelet count). β-Thromboglobulin (β-TG)and . platelet factor 4 (PF4) levels were measured by radioimmunoassay. The PA score correlated significantly (p < 0.0001) with β-TG (r = 0.86) and PF4 (r = 0.87). It was concluded that the PA score correlates closely with individual subjects' propensities to platelet activation, as reflected by plasma β-TG and PF4 levels. Key Words: Platelets-Platelet aggregometry-Platelet secretory proteins.

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