PB1180 - The differences and correlations of LTA results obtained using different sampling methods.

Background: The standardization of platelet function testing is essential. Closed evacuated blood collection tubes (EBCT) and open non-evacuated tubes (non-EBCT) are used for blood collection. The results of light transmission aggregometry (LTA) examination of samples obtained by these two sampling methods from the same person can differ.

Aims: 1. To evaluate differences between maximal aggregation with low concentrations of epinephrine and ADP using samples collected with EBCT and samples collected with non-EBCT.
2. To evaluate the correlation of maximal aggregation with low concentrations of epinephrine and ADP using samples collected with EBCT and samples collected with non-EBCT.

Methods: 100 healthy volunteers (50 men and 50 women) were investigated. The blood samples were drawn by venipuncture using EBCT and non-EBCT from every subject. The platelet pure plasma and platelet rich plasma were prepared according to standard protocol. The aggregation with ADP concentrations 2.5 µM, 1 µM, and 0.5 µM and epinephrine concentrations 10 µM, 1 µM, and 0.5 µM was investigated using the Sysmex CS-2500 analyzer. The STATISTICA.CZ software was used for statistical analysis; Shapiro-Wilk test was used for evaluation of distribution normality, Wilcoxon test was used for evaluation of median differences, and Spearman correlation coefficient was used for analysis of correlations.

Results: The aggregation of platelets prepared from samples obtained using EBCT was significantly enhanced compared to the aggregation of platelets prepared from samples obtained using non-EBCT with the exception of epinephrine 10 µM (Table No 1). The results of aggregation of platelets prepared from samples obtained using EBCT correlated strongly with the results of aggregation of platelets prepared from samples obtained using non-EBCT (Table No 2).

Conclusion(s): The EBCT and non-EBCT are acceptable for LTA with low concentrations of ADP and epinephrine; the sampling using EBCT seems to be more suitable for standardization of the procedure.