NEW AUTOMATIC TEST TO STUDY PLATELET RESPONSE TO OSMOTIC-PRESSURE VARIATIONS - APPLICATION TO ASSESSMENT OF PLATELET CONCENTRATES VIABILITY

Studying the osmotic resistance or swelling of platelets has often bee n suggested as a global test to assess the viability of those cells. A number of authors have also analysed the behaviour of platelets in hy potonic media by a variety of complementary methods (cell count, morph ology, determinations of substances released, photometric measurement of aggregation induced by aggregating agents, etc). Most studies are c urrently based on the so-called <<osmotic shock response>> test, which measures according to time the light transmitted through platelet-ric h plasma (PRP) after dilution in distilled water. In this study, the a uthors describe a new automated and reproducible test using slow dialy sis to assess platelet osmotic resistance. The <<Fragilimeter>>, a dev ice initially described by the authors to characterise RBC fragility, has been adapted to the study of platelet osmotic behaviour. The varia tions in light transmission through a platelet suspension according to NaCl concentration are linked to the change in cellular volume and ly sis and characterise the viability of the cells. The results obtained with normal platelets revealed the good reproducibility of the techniq ue. The osmotic resistance is evaluated for two parameters: anticoagul ant (citrate, EDTA) and cellular concentration. The test was applied t o quality control of stored platelet concentrates for transfusion, pre pared with different cell separators. (C) 1998 Elsevier, Paris.