ALS Diagnosis

Making an ALS diagnosis can be difficult. The reason for this is that it is considered a diagnosis of exclusion. This means that the diagnosis of ALS can only be made by confirming several different features of the disease and by ruling out (excluding) any other possible causes. There is no one test that can definitively establish the diagnosis of ALS in all patients.

For this reason, when the diagnosis of ALS is considered, there are several things that must be done as part of the diagnostic process. Of course one of the first steps is a thorough and complete neurological exam by a qualified physician, usually a neurologist. There are several other forms of testing that typically follow. Most or all of these are typically performed in all patients.

Other testing includes:

• Imaging studies - which can include x-rays, magnetic resonance imaging of the brain and/or spine, and myelogram of the spine.
• Function neuromuscular testing - including electromyography (EMG) and nerve conduction studies (NCS).
• Blood and Urinary Testing for various proteins, hormones and metals.
• Biopsy of nerves and/or muscles.

Which of these tests are performed and when is up to each treating physician. Based on the results of these tests and the neurological examination, physicians make the judgement whether this constitutes an ALS diagnosis or some other underlying causes. Because ALS is not curable and portends a poor prognosis, this diagnosis is not made lightly, only after weighing all the different options and excluding any other potentially treatable causes as thoroughly as possible. For this reason, most patients seek the second opinion of a neurologist or other physician who specializes in disorders related to ALS.