Rapid screening of dengue fever using research parameters from new generation hematological analyzers

The early diagnosis of dengue fever and its differentiation from other causes of acute febrile illness is essential for a better outcome. The new generation automated hematology analyzers provide parameters like high fluorescence lymphocyte count (HFLC) and leukocyte cell population data (CPD) representing various leukocytes. We tried to analyze the utility of these parameters in the rapid screening of dengue fever.

The HFLC and the leukocytic CPD from the Sysmex XN1000 analyzer were obtained for 299 cases presenting with acute febrile illness, which included 97 dengue-positive and 202 cases dengue-negative controls. Additionally, 100 healthy controls were also included. The Receiver operative curves (ROC) were drawn to obtain a cut-off value for these parameters for discriminating among the dengue-positive and dengue-negative subgroups and healthy controls.

The dengue-positive cases showed a significantly increased HFLC among the different groups of controls. The median (range) HFLC% was 1.9(0.30-6.55), 0.20(0.10-0.70), and 0.10(0.0-0.30) in the cases that were positive for dengue, negative for dengue, and healthy controls, respectively. The ROC analysis revealed HFLC% at a cut-off value of 1.75 which can discriminate between dengue-positive and dengue-negative patients, with 52% sensitivity, 90% specificity, 72% positive predictive value (PPV), and 80% negative predictive value (NPV). The regression analysis revealed LY-X, LY-Z, Ly-WX, LY-WZ, and MO-X as independent predictors for dengue fever.

The HFLC and CPD obtained from Sysmex XN1000 hematology analyzer are valuable tools in rapidly screening dengue infection from other febrile illnesses in routine practice.