Immature platelet fraction as a useful predictor of the aetiology of thrombocytopenia: experience from Oman

Abstract

Clinical evaluation of the possible aetiology of thrombocytopenia is important in the management of thrombocytopenia, which is concomitant with different disease processes. Thrombocytopenia can lead to a range of symptoms varying from petechiae and purpura to excessive bleeding from the mucocutaneous membrane, especially when severe. The aetiology of thrombocytopenia is usually not obvious, and different investigations are needed, including invasive methods such as bone marrow examination. The immature platelet fraction (IPF) (IPF%, the ratio of immature platelets to the total number of platelets in a patient’s blood) has emerged as a useful, easy, fast parameter for assessing thrombopoiesis in patients with thrombocytopenia. This assessment helps clinicians identify the underlying cause of thrombocytopenia, namely, increased peripheral platelet destruction or underproduction and thus can obviate the need for bone marrow examination. The primary objective of this study was to evaluate the usefulness of IPF in directing the end user towards the possible aetiology of thrombocytopenia in the Omani population. A secondary objective of the study was to determine the possible correlation between platelet count and IPF in patients with coronavirus disease 2019 (COVID-19) as an example of consumptive thrombocytopenia. IPF% was evaluated in 136 patients managed at the Armed Forces Hospital between April and September 2021 who were diagnosed with thrombocytopenia as a result of different diseases. Data from healthy people and patients were collected from the Sysmex XN blood cell counter database (IPF special channel) and analyzed using Minitab 17 Software. The patients with thrombocytopenia included patients with COVID-19 (n=61), patients with infection/sepsis (n=12), gestational thrombocytopenia (n=16), systemic lupus erythematosus (n=8), microangiopathic hemolytic anemia (n=2), sickle cell disease (n=11), or liver cirrhosis (n=24) and postchemotherapy patients (n=2). Compared with the 55 healthy control group (mean=4.28), the most significant rise in IPF% was observed in cases of increased peripheral platelet destruction/consumption, such as thrombocytopenia in COVID-19 (mean=16.23), infection/sepsis (mean=12.98), gestational thrombocytopenia (mean=17.62), systemic lupus erythematosus (mean=18.26) and microangiopathic hemolytic anemia (mean=10.60). Additionally, the mean IPF% was higher in patients with sickle cell disease and liver cirrhosis (7.44 and 5.45, respectively) than in patients in the control group but remained within the newly determined reference range of IPF% for the Omani population (0.2–8.36). The mean IPF% postchemotherapy (mean=4.70) was the closest to the control group mean. This is the first study to examine the utility of IPF% in identifying the aetiology of thrombocytopenia in an Omani population, and based on these data, we can conclude that IPF can be used as a first-line screening parameter that may add corroborative evidence for the differential diagnosis of the aetiology of thrombocytopenia. This study also reported a reference interval for IPF% in the Omani population (0.2–8.36) for the first time, independent of gender. Moreover, by studying the relationship between the IPF% and Platelets (PLT) count in COVID-19 patients, it was found that the IPF% increased with the decrease in the number of platelets. This finding suggests that IPF may have a role as a prognostic marker in these patients and may lead clinicians to suspect the development of complications.