Clinical Laboratory Science Practice Exam 2026 - Free Clinical Laboratory Science Practice Questions and Study Guide

In viral meningitis, the inflammatory response in the CSF is mainly driven by lymphocytes, so you see a rise in lymphocytes in the CSF cytology. This lymphocytic pleocytosis reflects the body’s adaptive immune response to viral infection. In contrast, bacterial meningitis typically shows neutrophil predominance because of the acute bacterial attack. Red blood cells would indicate bleeding rather than inflammation, and eosinophils are more associated with parasitic or eosinophilic meningitis. It’s also helpful to remember that early in viral meningitis you might see some neutrophils, but the pattern shifts toward lymphocytes as the illness progresses.