Laboratory Tests for Neuropathies: What to do and to Avoid

Abstract

Objectives: laboratory tests for work-up of hereditary and acquired neuropathies of peripheral nerves are frequently uncritically utilized. This overview focuses on the most common laboratory tests and investigations needed for diagnosing PNPs by the general neurologist.

Method: Literature search.

Results: laboratory tests recommended for the work-up of hereditary and acquired neuropathies should be chosen according to the individual and family history, clinical presentation, and electrophysiological findings. Laboratory tests should be selected specifically according to the suspected type of neuropathy to avoid unnecessary tests and expenses. Work-up should include as few samples as necessary for uncovering the etiology and should consider the sensitivity/specificity of the tests applied.. Basic screening tests for neuropathies should include a blood cell count, thyroid, renal and liver function tests, blood glucose levels, HbA1c, vitamin-B12, and immunofixation. Other laboratory investigations should be carried out only if a specific phenotype is present or if unexpected changes of the disease course occur. In these cases referral to a neuromuscular center is recommended.

Conclusions: Laboratory tests are helpful for the diagnosis of acquired and hereditary neuropathies but these tests should be ordered according to the history, clinical presentation and findings on electrophysiological investigations. If basic laboratory parameters fail to uncover the etiology, patients should be referred to a center specialized in neuromuscular disorders.

Keywords: Neuropathy; diagnosis; electromyography; hereditary; nerve conduction.