Exams and Tests

Diagnosing West Nile virus infections is generally done through a combination of observing signs and symptoms along with specialized molecular biologic testing for the virus itself.

• Only people with severe symptoms will require further testing. There is no cure for West Nile and therefore little to gain by widespread testing of people with mild symptoms. In addition, there is only limited laboratory capacity for testing at this time.

• Confirmatory diagnosis of West Nile virus infection is generally done by a DNA test called polymerase chain reaction (PCR) or viral culture of fluid around the spinal cord. A doctor  sends both blood samples and spinal fluid samples, obtained by lumbar puncture (also called a spinal tap), to a specialized outside laboratory for these tests.