INVESTIGATIONS OF PLATELET-AGGREGATION AND PLATELET COUNTS FROM STORED CANINE WHOLE-BLOOD

The effects of the long term storage of canine blood at 4 to 6 degrees C in pvc-bags containing CPDA-1 as a stabiliser on platelet aggregati on and platelet counts were investigated. Aggregation induced by colla gen, adenosine diphosphate or a calcium ionophore was preserved well d uring the first six hours, but there was then a decrease of 24 to 46 p er cent in the ability of the platelets to aggregate, after which duri ng the next three to four weeks of storage there was no further decrea se in their aggregation properties. The formation of aggregates of pla telets reduced the numbers of platelets counted as single thrombocytes by more than 30 per cent during the first four days. The numbers of p latelets recorded varied widely with the counting method used (countin g chamber or automatically) and with the ethylenediamine tetra-acetic acid content of the dilution fluid.