investigations

Last reviewed 02/2023

Key investigations in Guillain-Barre syndrome show:

  • CSF protein is elevated in most patients after the second or third week of illness. The gamma globulin fraction is usually raised. Cells, usually monocytic, are found in 20% of cases, but the characteristic appearance is one of an elevated protein level without cells.
  • nerve conduction - prolonged conduction velocities are a late phenomenon
  • virology - occasionally, rising titres to specific viruses may be found
  • Campylobacter serology should be performed as positive titres identify a group with a poorer prognosis

Forced vital capacity measurements should be used to assess the progression of the disease and predict the need for respiratory support.