What is the test for Guillain-Barré Syndrome (GBS)?

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Last updated: March 28, 2025View editorial policy

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From the Guidelines

Guillain-Barré Syndrome (GBS) is diagnosed through a combination of clinical examination, cerebrospinal fluid analysis, and electrodiagnostic testing, with the primary test involving a lumbar puncture to analyze cerebrospinal fluid, which typically shows elevated protein levels with normal cell counts (albuminocytologic dissociation) 1. The diagnosis of GBS is based on the patient's history and neurological, electrophysiological, and cerebrospinal fluid (CSF) examinations 1.

Key Diagnostic Tests

  • Lumbar puncture to analyze cerebrospinal fluid
  • Nerve conduction studies and electromyography to confirm the diagnosis
  • Blood tests to rule out other conditions and identify specific antibodies associated with GBS variants
  • MRI of the spine to exclude other causes of symptoms These tests should be performed promptly when GBS is suspected, as early diagnosis allows for timely treatment with immunotherapy such as intravenous immunoglobulin (IVIG) or plasma exchange 1.

Importance of Early Diagnosis

Early diagnosis is crucial, as approximately 20% of patients with GBS develop respiratory failure and require mechanical ventilation due to respiratory muscle weakness 1.

Diagnostic Criteria

The diagnostic criteria for GBS include progressive, relatively symmetric muscle weakness and diminished reflexes, with electrophysiological studies providing evidence of PNS dysfunction and distinguishing between the subtypes of GBS: acute inflammatory demyelinating polyradiculoneuropathy (AIDP), acute motor axonal neuropathy (AMAN), and acute motor sensory axonal neuropathy (AMSAN) 1.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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