Survival of Blood Platelets Labeled with Chromium5112

Various criteria exist for the evaluation of the integrity, viability and physiological activity of human blood platelets. Alterations in platelet morphology, clot promoting and clot retracting activities, oxygen consumption, clinical effect on bleeding disorders, and the life span of platelets in thrombocytopenic recipients have been used as measurements of platelet function. The transfu- sion studies in thrombocytopenic recipients indi- cate that platelets have a life span of three to seven days and have been helpful in the classification of certain pathological disorders (2). These ob- servations have been dependent upon obtaining donors with high platelet counts and accepting the errors associated with platelet counting. The diffi- culty in procuring adequate donors and the de- sirability of measurements other than platelet enu- meration have initiated numerous studies of the in vivo survival of platelets labeled with radio- active isotopes.