Immature platelets: A useful tool for thrombocytopenia etiology classification in adults

The etiology of thrombocytopenia is diverse with heterogenous clinical manifestations which demand the correct diagnosis and appropriate management. The immature platelet fraction is associated with new platelet release from the bone marrow by thrombopoiesis. The clinical utility of this low-cost, feasible measurement has been demonstrated across various conditions. This study aimed to assess the immature platelet fraction and count as diagnostic tests to distinguish between the two main causes of thrombocytopenia in selected hematology disorders.

A total of 444 participants were evaluated: Group 1 (n = 179; healthy blood donors), Group 2 (n = 131; peripheral platelet destruction or consumption, including immune thrombocytopenia and thrombotic thrombocytopenic purpura), and Group 3 (n = 134; bone marrow failure secondary to aplastic anemia, chemotherapy, acute leukemia, or multiple myeloma).

Median immature platelet fraction (%) and immature platelet count (× 10⁹/L) values were 3.3/8.1 (Group 1), 16.5/6.1 (Group 2), and 5.0/1.8 (Group 3), with significant intergroup differences between Groups 2 and 3 (p-value <0.001). Optimal diagnostic cut-offs were 8.3% for immature platelet fraction (AUC = 0.8585) and 3.1 × 10⁹/L for immature platelet count (AUC = 0.7687). The immature platelet fraction was highest in immune thrombocytopenia patients and showed significant inverse correlations with platelet counts in Groups 1 and 2 (p-value <0.001).

Immature platelet fraction and immature platelet count can be useful to discriminate between the main etiologies and should be included in the routine of hematology centers for screening thrombocytopenia.