Increased reticulated platelets in dialysis patients.

The purpose of this study was to measure the percent reticulated platelets and platelet counts in patients on chronic hemodialysis, peritoneal dialysis and normal volunteers. The relationship between the percent reticulated platelets and the platelet count can then be used to determine the rate of platelet turnover. Platelet rich plasma was obtained, platelets were fixed and incubated with thiazole orange and analyzed for the percent reticulated platelets by flow cytometry. Normal controls had a mean of 2.77 +/- 0.17% reticulated platelets while peritoneal dialysis patients had a mean percent reticulated platelets of 6.92 +/- 0.68 (P < 0.00001). Chronic hemodialysis patients had a mean percent reticulated platelets of 8.21 +/- 0.36 (P < 0.00001 vs. normal controls and P = 0.05 vs. peritoneal dialysis patients). Platelet counts did not differ significantly among the three groups. The identity of reticulated platelets was confirmed in experiments measuring platelet specific glycoproteins, experiments using RNase, and in mixing experiments with normal and uremic platelets and plasma. We conclude that dialysis patients have a marked increase in circulating reticulated platelets compared to normal controls, indicating accelerated platelet turnover. Increased platelet activation and turnover may contribute to the qualitative platelet dysfunction observed in dialysis patients.