Exams and Tests

No one test gives a definitive diagnosis of ALS. If you are having symptoms that suggest ALS, your health care provider will conduct a complete workup. He or she will conduct a detailed medical interview and physical examination and review the results of various tests before arriving at a diagnosis. At any time during the workup or treatment planning, your healthcare provider may refer you to a specialist in diseases of the nervous system (neurologist).

Your healthcare provider will ask you many questions about:

• your symptoms;
  
  
• your medical problems now and in the past;
  
  
• the medical problems of your family members;
  
  
• the medications you take;
  
  
• your work, military, and travel experiences;
  
  
• your habits and lifestyle; and
  
  
• probably others.

A detailed physical examination will focus on your mental abilities, movements, sensations, and reflexes.

Lab tests

There is no lab test that confirms the diagnosis of sporadic ALS. Your healthcare provider may order a number of blood tests. Many of these are used to rule out specific conditions that may cause the symptoms you are having. These conditions include infections, metabolic problems, and autoimmune conditions. It is important to distinguish ALS from other conditions because many of these conditions can be improved with appropriate treatment.

Imaging studies

You may undergo magnetic resonance imaging study (MRI) of the brain or spinal cord. MRI findings are normal in ALS, but these studies may be needed to rule out other conditions whose symptoms are similar to those of ALS.

Other tests

Needle electromyography (EMG) and nerve conduction studies are the tests of choice for confirming the diagnosis of ALS. They also can rule out certain other conditions that may be confused with ALS.

• EMG is a method of recording electrical activity in muscles. Certain EMG findings support the diagnosis of ALS.
  
  
• Nerve conduction velocity (NCV) measures the impulses traveling through nerves between the spinal cord and muscles. This test can distinguish between ALS and other conditions with similar symptoms.
  
  
• These tests are conducted by a physician who specializes in electrophysiologic measurements.

In certain circumstances, a muscle biopsy is done to rule out muscle diseases that may have similar symptoms. A biopsy is removal of a tiny piece of tissue. The tissue is tested and examined under a microscope by a physician called a pathologist. The pathologist reports his or her findings back to the physician who ordered the biopsy.