How is viral meningitis diagnosed?

Viral meningitis is usually diagnosed by laboratory tests of spinal fluid obtained with a spinal tap. The specific cause of viral meningitis can be determined by tests that identify the virus in specimens collected from the patient, but these tests are rarely done.


Meningitis is diagnosed by a lumbar puncture, or spinal tap, in which a doctor inserts a needle into the lower back to obtain a sample of CSF. The fluid is then tested for the presence of bacteria and other cells, as well as certain chemical changes that are characteristic of meningitis.