White Blood Cell Count Interpretation in Children

Clinical Significance of WBC Values

• A low WBC count (<5,000 cells/mm³) may indicate viral infections, particularly influenza A in children, with studies showing WBC <4,000 occurs in 8-27% of children with influenza A 1, 2
• A very low WBC count (<1,500 cells/mm³) with lymphopenia may indicate severe infection 1
• A high WBC count (>15,000 cells/mm³) is found in only 8-12% of children with influenza A and may indicate bacterial infection, inflammation, or stress response 1, 2
• Both very low and very high WBC counts can indicate serious illness 2
• In severely ill children, a full blood count with differential, along with other laboratory tests, should be performed 1, 2