Free BCEN Certified Emergency Nurse (CEN) Practice Question

Lumbar puncture with cerebrospinal fluid (CSF) analysis is the best initial diagnostic test for Guillain-Barré syndrome (GBS). In GBS, the CSF typically shows elevated protein levels with a normal white blood cell count, a finding known as albuminocytologic dissociation. This characteristic CSF profile is crucial for diagnosis and differentiating GBS from other conditions.

While nerve conduction studies are also important in diagnosing GBS, they are often performed after the initial CSF analysis and may not show abnormalities in the early stages of the disease. MRI of the spine can be useful to rule out other causes of weakness but is not the primary diagnostic tool for GBS. Blood tests for anti-ganglioside antibodies can support the diagnosis but are not routinely used as an initial diagnostic test due to their lower sensitivity and specificity compared to CSF analysis.