Introduction: Dengue affects 2.5 billion people globally, with symptoms ranging from mild flu-like illness to fatal Dengue Hemorrhagic Fever (DHF). Diagnosis is confirmed using Dengue virus ELISA IgM and NS1 antigen. High Fluorescent Lymphocyte Count (HFLC), measured using the Sysmex XN-1000 hematology analyzer, provides a faster, cost-effective, and accurate alternative to ELISA and NS1 tests. Study Aims: 1. To determine HFLC in Dengue Fever (DF) and DHF patients using the Sysmex XN-1000. 2. To assess the correlation of HFLC with thrombocytopenia, particularly from day 1 to day 5 of infection. Methods: A cross-sectional study was conducted at two tertiary care hospitals in India (Aug–Oct 2024) with IEC approval. A total of 52 patients of all ages, positive for NS1 antigen and/or ELISA IgM, were included. Routine venous blood samples were analyzed via Sysmex XN-1000. Data on CBC, total cell count, hemoglobin, liver enzymes, and HFLC were tabulated in Excel and analyzed using SPSS 20.0. Results: Among 52 DF patients, HFLC ranged from 0.1–20.3%, with a mean of 8.5%. Of these, 15 had DHF, showing low HFLC (0.1–3.2%), averaging 1.2% (TABLE 1), correlating with high NS1 titers and reduced immune response. A significant difference in HFLC% between DF and DHF patients was observed (p 5 days, correlating with high IgM titers. Abnormal USG findings (e.g., gallbladder wall edema/capillary leak) were seen in 33% and significantly correlated with HFLC (p = 0.001). DHF patients with low HFLC had longer hospital stays (8 ± 2.2 days), which was statistically significant (p < 0.5). Conclusions: HFLC is a promising research parameter for assessing Dengue severity. This is the first known study to report a positive correlation between HFLC and thrombocytopenia in DHF patients, with limited prior literature available.
Kaur et al. (Sun,) studied this question.