Applications of Extended Platelet Profiles in Clinical Practice

Thrombocytopenia is a frequent complication of patients presenting emergently across the world for a wide array of etiologies. From patients who develop thrombocytopenia due to invasive neoplastic disease affecting the bone marrow to patients who developed immune-complications secondary to formation of auto-antibody responses that drive patients’ platelets counts lower or even infection, stress the clearest need of prompt tests to discern the more likely thrombocytopenic-inducing cause. It is in this setting that looking at other platelet variables easily obtainable from modern hematology analyzers have gained traction. One of these elements found in extended platelet profiles are immature platelets (youngest and newly released platelets) also known as reticulated platelets depending upon the platform performing the measurement. Among the advantages of obtaining these counts is that it represents the immediate responses by the bone marrow to the thrombocytopenia and depending on etiology inducing the thrombocytopenia it also provides information of the marrow response to therapeutic approaches. It is in this context that this review will present information of how these relatively novel platelet parameters can be used in clinical practice and how they can be a rapid gauge of the body’s response to disease processes leading to thrombocytopenia. Thrombocytopenias resulting from infection (sepsis), autoantibody formation (immune thrombocytopenia and immune-mediated thrombotic thrombocytopenic purpura), immune dysregulation (systemic lupus erythematosus), and iatrogenic (drug-induced) will be discussed and be used to explain how these young platelet measurements can provide valuable clinical information.