06/10/2026
When dengue NS1 antigen and antibody tests come back negative during the acute phase, clinicians face a diagnostic gap at the moment it matters most. This case report followed a 21-year-old patient through secondary dengue infection, from a negative NS1 result on day 3 through seroconversion on day 11. While standard serological markers missed the window, serial complete blood counts performed on the HORIBA Yumizen H500 hematology analyzer captured the immune response in real time.
Extended white blood cell differential parameters, including immature granulocytes, immature monocytes, atypical lymphocytes, and large immature cells, tracked the activation of both innate and adaptive immune responses as the disease progressed. Inflammatory indices calculated from the same CBC data (neutrophil-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, platelet-to-lymphocyte ratio) reflected clinical deterioration and recovery in parallel with the patient's course.
These parameters are repeatable, practical, and cost-effective. In resource-limited settings where advanced serological testing may not be readily available, they offer a way to monitor disease progression using equipment already present in the laboratory.
