The Utility of the Laboratory Work Up at the Time of Diagnosis of Amyotrophic Lateral Sclerosis.

BACKGROUND

Serological testing is routinely performed in the work up for a diagnosis of Amyotrophic Lateral Sclerosis (ALS) to exclude pathologies with similar clinical phenotypes.

OBJECTIVE

To determine the proportion of serological workup that changes the primary diagnosis and/or clinical management for patients presenting with signs of ALS.

METHODS

A retrospective chart review was conducted on patients from the Calgary Neuromuscular Intake Clinic in which the neurologist working diagnosis post-assessment is ALS. Charts from 2012 to 2016 with completed standard serological workup were reviewed. The proportion of abnormal results per investigation was determined and whether it resulted in a change in diagnosis and/or clinical management.

RESULTS

A total of 276 charts were reviewed and 85 met full inclusion criteria. Serum creatine kinase (35%), vitamin B12 (18%), complete blood count with differential (11%), and parathyroid hormone (10%) were the among the investigations that had a proportion of abnormal results greater than 5%. Only 6% of patients had an abnormal result that qualified for a change in their clinical management none of which changed the primary diagnosis of ALS.

CONCLUSIONS

Standard serological investigations in the work-up for a patient with ALS may have low utility from a diagnostic and management perspective.