DIFFERENCES IN PLATELET COUNT AND SIZE BETWEEN MARROW AND PERIPHERAL-BLOOD

Automatized platelet parameters were evaluated in 23 unselected patien ts undergoing a bone marrow examination for diagnostic purposes, both in medullary and in peripheral blood, with the aim of investigating th e biological significance of platelet volume heterogeneity. In the mar row blood the platelet count was 10.07+/-21.25% (p <0.05) lower and th e platelet volume 7.93+/-6.88% (p <0.001) higher compared to periphera l venous blood: 275,173+/-108,079 versus 296,652+/-104,814/mm(3) (p <0 .05) and 8.93+/-1.46 versus 8.23+/-1.57 fl (p <0.001), respectively. T he same behavior was observed between the marrow and the arterial bloo d collected from 12 out of the 23 patients, while no significant diffe rence was observed between arterial and venous blood. The differences observed might be attributable to a platelet population replacement un der homeostatical regulation and seem to support the concept that the large platelets are younger elements.