Thrombopoiesis and thrombokinetics--an approach to the evaluation of thrombocytopenia.

Thrombocytopenia is a common clinical disorder with a diverse group of etiologies. Traditionally, the approach to identifying the mechanism of thrombocytopenia has been empirical, primarily due to a lack of clear understanding of normal thrombopoiesis and its control. Additionally, readily available clinical measurements that reflect patterns of altered thrombopoiesis are unavailable. Recent experimental and clinical observations permit us to approach this disorder from a kinetic point of view to classify thrombocytopenia by four mechanistic categories: peripheral destruction and consumption, hypoproliferative thrombocytopenia, ineffective thrombopoiesis, and distributional causes. The application of the measurement of mean platelet size, in conjunction with a bone marrow examination, allows the clinician to more readily identify the cause of a low platelet count in a less empirical manner.