Effect of cold exposure on platelet concentrates: changes in platelet indices and aggregation states.

Samples from platelet concentrates (filtered/non-filtrated, at the beginning/the end of shelf life) were exposed to 4 degrees C overnight, subsequent to dilution in platelet storage media (PSM) and/or exposure to EDTA to induce shape changes. Paired sampling protocol (+/- EDTA) was used and changes in cellular indices and induced-aggregation states were measured by Technicon H*1. Cold induced changes in platelets as identified by increase in MPV (0.5-0.8 fL for EDTA; 1.5-2.0 fL for citrated samples) with concomitant reverse changes in PDW ranging from 2-13 per cent was observed. Processing, storage and cold exposure also induced disparity between leucocyte peroxidase/basophil counts. This in conjunction with changes in platelet counts and cellular indices upon exposure to EDTA provide a unique new tool for assessing the aggregation states of platelets during processing and storage. Both filtration and dilution in PSM affect platelet storage stability. Platelets which have already undergone shape changes (i.e. exposure to EDTA) responded to a lesser degree to cold exposure. Our findings indicate that platelets's response to cold exposure can be used as a simple, reliable and accurate test for assessment of platelet morphological and function integrities.