Clinical Testing and Diagnosis for Tick-borne Encephalitis

Key points

  • Serologic testing is the primary method for diagnosing tick-borne encephalitis (TBE).
  • Serologic cross-reactivity can occur with Powassan virus, a related domestic tickborne arbovirus.
  • TBE virus-specific neutralizing antibody testing can be performed at CDC to confirm TBE.
  • Contact your state or local health department for assistance with diagnostic testing.
lab worker performing a diagnostic test

Recommended tests

In the United States, diagnostic testing for TBE can be performed at CDC. Evidence of recent infection is typically based on detection of specific immunoglobulin (Ig) M in serum or cerebrospinal fluid (CSF). TBE virus is closely related to Powassan virus, a domestic arbovirus also transmitted by ticks, and serologic cross-reactivity can occur. Therefore, testing for TBE virus-specific neutralizing antibodies is used to confirm a positive IgM result to diagnose TBE.

Virus isolation or detection of viral RNA by reverse transcription-polymerase chain reaction (RT-PCR) in CSF or serum can also be used to diagnose TBE, but these are rarely positive. Patients who are immunocompromised might require these tests for diagnosis.

To submit specimens for testing, please contact your state or local health department. They can assist you with determining if samples should be sent to the CDC Arbovirus Diagnostic Laboratory for further testing. Specimens should be submitted to CDC through state health departments. All results will be sent from CDC to the appropriate state health department.