Reticulated platelet counts in the assessment of thrombocytopenic disorders

Reticulated platelets (RP) are the youngest platelets in the circulation and can be measured by analysing the RNA content of platelets from whole blood or platelet-rich plasma by flow cytometry. Increased RP are indicative of increased production of platelets. Despite the current lack of standardization for the measurement of RP, it is useful in the assessment of patients with ITP by aiding the distinction of these patients from those with decreased platelet production. RP counts also have a role in the assessment of the complicated patient with multiple possible aetiologies for thrombocytopenia. Measurement of the RP count may hold predictive value for marrow recovery following myelosuppressive or myeloablative chemotherapy, and may play a role in monitoring the administration of the various thrombopoietins currently under clinical trial.