Correlation between immature platelet fraction and reticulated platelets. Usefulness in the etiology diagnosis of thrombocytopenia

Background: Reticulated platelets (RP) are a surrogate marker for megakaryocytic activity, but the limitation of this determination is the lack of standardization of methodology. The determination of the immature platelet fraction (IPF) is performed in a simple, automated, and reproducible way between laboratories. We analyzed the correlation between IPF and RP, and usefulness of IPF in patients with thrombocytopenia. Methods: RP were determined by flow cytometry using double staining with thiazole orange and CD61 PerCP^®. IPF was performed with Sysmex XE2100 analyzer. We used a control group with normal platelets, and thrombocytopenic patients were classified into three groups: Group 1. Central thrombocytopenia, Group 2. Thrombocytopenia as a result of enhanced peripheral platelet destruction, and Group 3. Peripheral non‐immune thrombocytopenia by abnormal distribution. Results: Fourteen controls and 66 patients were analyzed. Group 1: 25 patients, they had mean and confidence interval 95% (95% CI) for IPF 8.67% (6.49–10.46%) and RP 4.08% (2.86–5.30%). Group 2: 20 patients, they had mean and 95%CI for IPF 16.80% (12.20–21.39%) and RP 16.14% (9.89–22.40%). Group 3: 21 patients, they had mean and 95% CI for IPF 9.04% (6.95–11.14%) and RP 5.23% (3.41–7.05%). The overall Pearson linear correlation between IPF and RP was r: 0.65. There were statistically significant differences in values of IPF and RP between Group 2 and the other two groups (P < 0.01). Conclusion: There is a good correlation between IPF and RP mainly in thrombocytopenia by peripheral destruction. Determination of IPF is an easy technique in their implementation, standardized and reproducible, so it could be a useful screening technique in patients with thrombocytopenia.