Immature Platelet Fraction As a Measure of Thrombocytopenia in Trauma Patients and Its Cut off Value with Severity of Thrombocytopenia
Authors: Shah Bhaumik Arvindkumar , Subramanium Arulselvi , Pati Hara prasad , Sharma Subhadra , Agrawal Deepak , Ahuja Rajesh , Mukhopadhyay Asok Kumar 
Published: October 2019

Abstract
Abstract 4681
Thrombocytopenia is common finding in trauma patients. However, platelet count fluctuates widely. Therefore, Immature Platelet Fraction is being studied for whether it can complement the platelet count.
Immature platelet fraction (IPF ) is a measure of reticulated platelets (RPs), which represents the state of thrombopoiesis. IPF is obtained from an automated haematology analyzer. It is proportional to reticulated platelets and expressed as percentage of Total optical count.

Aim
To establish cut off value of IPF (%) with increasing severity of thrombocytopenia in trauma patients which can be useful for diagnosis and monitoring of the cases.

Material and methods
Total 69 patients admitted in J.P.N Apex trauma centre (AIIMS) were studied within first 24 hrs after injury. Peripheral blood was collected in K2EDTA tube for measurement of platelet count using a fully automated analyzer Sysmex XE 2100 (Japan). RET channel was selected for the measurement of IPF%.The patients were categorized with platelet count between 150×103/μ l and 100×103/μ l, between 100×103/μ l and 50×103/μ l, and below 50×103/μ l. Immature platelet fraction was measured in all categories of thrombocytopenia and statistically compared. Each patient was ascribed New Injury Severity Score and SOFA (sequential organ failure assessment) score and their correlation with IPF value was assessed. ROC curve was used to establish cut off value of IPF between those with platelet count above150×103/μ l and below 150×103/μ l and between those with platelet count above 100×103/μ l and below 100×103/μ l.

Results
Using Mann Whitney test, the patients (n=41) with platelet count < 150×103/μ l showed mean IPF (%) (18.19 ± 9.43, range: 4.0 – 46.6) which was significantly higher (p<0.0001) than that of subjects (n=28) with platelet count above 150×103/μ l,in which mean IPF (%) value was (8.94 ± 5.79, range:2.3 − 24.9).
The cut–off value of IPF > 12.5% was found in patients having platelet count < 150×103/μ l.
Similarly, the patients (n=22) with platelet count < 100×103/μ l showed mean IPF (%) (22.04 ± 9.94, range:10.8-46.6) which was significantly higher (p<0.0001) than that of patients (n=47) with platelet count above 100×103/μ l in which mean IPF (%) value was (10.87 ± 6.51, range:2.3 − 35.4).
The cut–off value of IPF > 14.95 % was found in patients having platelet count <100×103/μ l.
Using Kruskal-Wallis test, IPF (%) value (23.31 ± 10.44, range: 11.2 – 46.6) in patients (n=18) with platelet count between (50×103/μ l – 100×103/μ l) was found to be significantly higher (p=0.003) than the value (13.73 ± 6.58, range: 4 – 35.4) obtained in patients (n=19 ) with platelet count between (100×103/μ l – 150×103/μ l).
No statistical significance was found between IPF (%) value (13.73 ± 6.58, range: 4 – 35.4) obtained in patients (n=19) with platelet counts between (100×103/μ l – 150×103/μ l) and IPF(%) value (16.3 ± 4.41, range:10.8-20.3) in patients (n=4) with platelet count below 50×103/μ l. Similar result was obtained between IPF(%) value (23.31 ± 10.44, range:11.2-46.6) in patients (n=18) with platelet count between (50×103/μ l – 100×103/μ l) and IPF(%)value (16.3 ± 4.41,range:10.8-20.3) in patients (n=4) with platelet count below 50×103/μ l.
IPF value (19.64 ± 7.88, range:6.6 − 35.4) was found to be significantly higher (p<0.0001) in patients (n=19) with SOFA score ≥8 as compared to the patients with SOFA score <8,which showed IPF (%) value (12.46±9.10, range:2.3-46.6). In contrast, no significant difference in IPF value was found in the context of New ISS score.

Conclusion:
Immature platelet fraction could be a reasonable and reliable measure of thrombocytopenia which can be used to diagnose and monitor the severity of thrombocytopenia in trauma patients.

Disclosures:
No relevant conflicts of interest to declare.