Abstract
BACKGROUND: Dengue infection (DI) is a significant global health concern, with severe cases leading to plasma leakage, organ failure, and shock. Identifying reliable biomarkers for early risk stratification is crucial for improving patient management. METHODS: This descriptive cross-sectional study included 268 DI patients at 103 Military Hospital, Vietnam, from July 2022 to October 2023. Patients were classified into Non-Severe DI and Severe DI groups per the 2009 WHO dengue guideline. High Fluorescent Lymphocyte Count (HFLC), a parameter from the Sysmex hematology analyzer, was analyzed. HFLC% represents the proportion of high fluorescent lymphocytes among total WBCs, while HFLC# is these cells' absolute count (G/L). Statistical methods included Mann-Whitney U, Kruskal-Wallis, Chi-square tests, ROC curve analysis, and binary logistic regression. RESULTS: HFLC% and HFLC# were significantly elevated in Severe DI compared to Non-Severe DI (p < 0.001). HFLC% negatively correlated with platelet count and positively with liver enzymes (AST, ALT), suggesting an association with severe complications. ROC analysis showed that HFLC# (AUC = 0.913, p < 0.001, cut-off = 1.00 G/L) had 70.6% sensitivity and 90.8% specificity, while HFLC% (AUC = 0.833, p < 0.001, cut-off = 13.15%) had 70.6% sensitivity and 80.5% specificity for predicting severe DI. CONCLUSION: Elevated HFLC at admission is strongly associated with severe DI, with HFLC# demonstrating excellent predictive accuracy. These findings suggest that HFLC is a promising biomarker for early identification of high-risk dengue patients. Further large-scale validation is required to confirm its clinical utility.