Distinction between hereditary macrothrombocytopenias(HM) and immune thrombocytopenia (ITP) can be challenging due to the lack of specific tests, increasing the risk of misdiagnosis and incorrect treatments. Previous studies have shown that the immature platelet fraction (IPF) values are influenced by platelet size and could be a convenient parameter when segregating from these two differential diagnosis of thrombocytopenia.

In this study, we have tried to further understand the usefulness of IPF as a screening tool for macrothrombocytopenias, as well as its correlation with platelets diameters in thrombocytopenias of distinct etiologies.

IPF, mean platelet volume (MPV) and mean platelet diameter (MPD) were analyzed using samples from 111 patients with different etiologies of thrombocytopenias: Immune thrombocytopenia (n = 39), bone marrow failure (n = 25), Hypersplenism (n = 30), type 2B Von Willebrand (VW) disease(n = 4), hereditary macrothrombocytopenias (n = 13).

Higher IPF values were observed in the ITP(9.8; 3.9-32), HM(26.7;14.4-55.4) and type 2 VW(35.1; 27.6-47.4) groups. On the last one, artificially increased IFP values were observed as a result of platelets aggregates. Applying a ROC analysis, IPF had a diagnostic accuracy of 0.96(95% CI:0.86 - 0.99; p < 0.0001) to distinguish between HM and ITP.

IPF is increased in HM compared to other thrombocytopenias and could be used as screening tool in the approach of HM patients.