@article{article_391737, title={The Unforeseen Effects of Stirring Plasma Samples From the Top Rather Than the Bottom on Aggregation in the Aggregometer}, journal={Journal of Uludağ University Medical Faculty}, volume={39}, pages={157–164}, year={2013}, author={Sağdilek, Engin and Sebik, Oğuz and Çelebi, Gürbüz}, keywords={Platelet. Aggregometry. ADP. Collagen. Epinephrine}, abstract={Aggregometry are considered the “golden standard” in assessing platelet aggregation. This study evaluates the differences observed when the plasma sample in the aggregometer was stirred from the top using a mechanical system compared to conventional method of stirring from the bottom of the plasma sample. Blood from healthy volunteers were anticoagulated using citrate (n=27) or heparin (n=26). Using the same stimulating agent, two samples from the same plasma were evaluated simultaneously in the two channels of the aggregometer; in one channel the plasma sample was stirred conventionally from the bottom, in the other channel the sample was stirred from the top using a mechanical stirrer. The maximum values, lag times and slopes of the resulting aggregation curves were measured. Stirring the plasma sample from the top using a mechanical stirrer resulted in a smaller value for maximum aggregation, preventing the aggregates to settle at the bottom. It also resulted in shorter lag times for collagen induced aggregations, and monophasic aggregation curves for epinephrine induced aggregations. The slopes of the aggregation curves for ADP and collagen induced aggregations were also lowered. The unforeseen effects of a simple modification of the classical method of aggregometry used for evaluating the aggregation process of platelets highlight the need to evaluate results from aggregometry in a different light.}, number={3}, publisher={Bursa Uludağ University}