BACKGROUND: Dengue fever is the most prevalent mosquito-borne viral disease in humans. Platelet indices (PIs) are given by the cell counters but are often not reported which is possibly due to under-recognition of the utility of these parameters.
OBJECTIVE: This study aimed to compare PIs in patients with dengue fever to assess their role in the outcome such as hospital stay and platelet transfusion requirements.
METHODS: Prospective observational study in a tertiary care center, Thrissur, Kerala.
METHODS: A group of 250 dengue patients was studied over a period of 18 months. The platelet parameters (platelet count, mean platelet volume [MPV], platelet distribution width [PDW], platelet large cell ratio [PLCR], plateletcrit [PCT] and immature platelet fraction [IPF]) were measured with Sysmex XN-1000 and followed up every 24 h. The clinical features, duration of hospital stay and platelet transfusion requirements details were collected.
METHODS: Independent t-test, Chi-square test, Karl Pearson correlation coefficient.
RESULTS: A total of sample size was 250. The study showed normal PDW and MPV, low platelet count and PCT, and high PLCR and IPF in dengue patients. There were significant differences in PIs (lower platelet count and PCT, higher MPV, PDW, PLCR, and IPF) in comparison between dengue patients based on platelet transfusion.
CONCLUSIONS: PIs may act as a predictive tool in the diagnosis and predicting outcomes in dengue fever. Low platelet count and PCT, high PDW, MPV, PLCR, and IPF in transfused dengue patients were found to be statistically significant. Clinicians need to be sensitized about the utility and limitations of these indices and rationalize the need for red cell and platelet transfusions in dengue.

BACKGROUND: There is a paucity of predictive factors for early recovery from thrombocytopenia related to dengue. The immature platelet fraction (IPF%) is reflective of megakaryopoiesis and may correlate with recovery from dengue-related thrombocytopenia. Our objective was to assess the predictive value of IPF% on days 2 and 3 of illness for recovery from dengue-related thrombocytopenia.
METHODS: A prospective study was conducted among patients with dengue admitted to our institution (Nawaloka Hospital PLC) from December 2019 to October 2020. Dengue was diagnosed based on positive non-structural antigen 1 or IgM. IPF% data were extracted from the Sysmex-XN-1000 automated hematology analyzer. Clinical data were obtained from electronic medical records. Statistical analyses were performed using SPSS version 20.
RESULTS: We included 240 patients. An IPF% on day 2 of illness of >7.15% had a sensitivity of 80.0% and specificity of 70.4% for prediction of platelet recovery (defined as platelet count ≥60×109/L) on day 7 of illness. An IPF% of >7.25% on day 3 of illness had a sensitivity of 88.9% and specificity of 47.1% for predicting platelet recovery >60×109/L on day 8 of illness. The IPF% was significantly lower in patients with severe dengue. Platelet recovery was observed within 48 h after the peak IPF% was reached, regardless of severity.
CONCLUSIONS: We propose that IPF% values on days 2 and 3 of illness are a promising predictive tool for early recovery from dengue-related thrombocytopenia.

Introduction Immature platelet fraction (IPF) is a parameter of an automated hematologic analyzer and is related to platelet size and cytoplasmic RNA content. It reflects thrombopoiesis and is often used as the marker of platelet activity. IPF has been evaluated mostly in hematologic disorders and has also been evaluated in patients with gestational hypertension, sepsis, autoimmune diseases and in hospitalised patients with neutrophilia. Platelets, asides from the maintenance of hemostasis, release inflammatory mediators that can modify leukocyte and endothelial responses to various inflammatory stimuli. Lower respiratory tract infections are the leading cause of death from infections worldwide. The role of platelets in lower respiratory tract infections has been reported in many studies. IPF, which is related to platelet activation, has not been evaluated in patients with lower respiratory tract infections. Methods The study involved patients who fulfilled the criteria of community-acquired pneumonia (CAP) and aspiration pneumonia (AP). In addition, age and sex-matched healthy controls were involved. Whole blood samples were collected from healthy controls and from the patients on admission. The mean IPF% and C-reactive protein (CRP) levels were measured in patients with CAP, in patients with AP and in healthy controls. The mean IPF% values in patients with infection were compared to mean IPF% values in healthy controls. The mean IPF% values were compared to mean CRP levels in patients with infection. Additionally, the mean IPF% values in patients that died in the first 14 days were compared to the mean IPF% values in patients that were alive. The statistical analysis of data was performed with the Statistical Package for the Social Sciences (SPSS) for Windows, Version 13.0 (SPSS Inc, Chicago, IL).  Results The study population consisted of 45 patients (27 patients with CAP and 18 patients with AP), 27 males and 18 females, with a mean age of 72.11 ± 16.4 years and 39 healthy controls, 22 males and 17 females with a mean age of 64.2 ± 14.8 years. The mean CRP levels in patients with infection were 155.2±119.1 mg/dl. The mean IPF% value of patients with infection was 2.76 ± 2.27 and the mean IPF% value of controls was 1.72 ± 0.77 (p < 0.006). The IPF% value in patients with CAP was 2.55 ± 2.02 and in patients with AP 3.07 ± 2.64 (p = 0.595). The mean IPF% value in patients with infection had no linear correlation with CRP value in these patients (r = 0.076, p = 0.62). The mean IPF% value in all patients that died in the first 14 days was 3.75 ± 2.44 and the mean IPF% value in all patients alive was 2.35 ± 2.11 (p = 0.06). The mean IPF% value in patients with CAP who died in the first 14 days of hospitalisation was 5.54 ± 3.17 and in patients with CAP who were alive was 1.87 ± 0.72 (p = 0.06). The mean IPF% value in patients with AP who died was 2.63 ± 0.85 and in patients with AP who were alive was 3.41 ± 3.51 (p = 0.554). Conclusions Mean IPF% value is greater in patients with lower respiratory tract infections, including CAP and AP, compared to healthy controls. There is no linear correlation between IPF values and CRP values in patients with lower respiratory tract infections. In addition, there is a difference in mean IPF% value between patients who died in the first 14 days of hospitalisation compared to those who were alive, but not statistically significant.

Immature platelet fraction (IPF) represents the quote of younger and larger sized circulating platelets, a potential marker of platelet reactivity and major cardiovascular events. We aimed to assess the relationship between IPF levels and the prevalence and extent of coronary artery disease (CAD) in patients undergoing coronary angiography.
A cohort of consecutive patients undergoing coronary angiography in a single centre were included. Significant CAD was defined as at least 1 vessel stenosis >50%, while severe CAD was defined as left main and/or three-vessel disease. IPF levels were measured at admission by routine blood cells count (A Sysmex XE-2100).
We included 1789 patients, divided according to quartiles values of IPF. IPF levels were directly related to active smoke (p = 0.02), and non-acute coronary syndrome as indication to angiography (p < 0.001), higher levels of haemoglobin and uric acid (p < 0.001, respectively) and lower platelet count (p = 0.003). Angiographic features did not significantly differ according to quartiles values of IPF, but for a lower degree of TIMI flow in patients with a higher percentage of reticulated platelets (p = 0.01) and a higher rate of lesions involving bifurcations (p = 0.05). IPF levels did not affect the prevalence of CAD (77% vs. 82.2% vs. 79.1% vs. 75.6%, p = 0.34, adjusted OR [95% CI] = 0.93 [0.82-1.05], p = 0.22), nor of severe left main/three-vessel CAD (28.5% vs. 34.4% vs. 32.2% vs. 33.1%, p = 0.27; adjusted OR [95% CI] = 0.99 [0.90-1.1], p = 0.88).
The present study shows that among patients undergoing coronary angiography, the immature platelet fraction (IPF) is not associated with the prevalence and extent of coronary artery disease, and, therefore, should not be overlooked as a marker of coronary atherosclerosis.