Detection and quantification of circulating immature platelets: agreement between flow cytometric and automated detection.

Immature platelets-also termed reticulated platelets (RP)-are platelets newly released into the circulation, and have been associated with a variety of pathological thrombotic events. They can be assessed by flow cytometry after staining with thiazole orange (TO) or by using a module added to a fully automated analyzer that is currently in wide clinical use and expressed as a fraction of the total platelet count (IPF). We sought to assess the correlation and agreement between these two methods.

Immature platelet fraction (IPF) determined with an automated method predicts clopidogrel hyporesponsiveness.

The mechanisms for the variability in antiplatelet effects of clopidogrel are not elucidated entirely. Immature (reticulated) platelets may modulate the antiplatelet effects of clopidogrel but must be measured using flow cytometry. Whether new automated detection techniques yield similar results is not known.