Diagnosing peripheral neuropathy can be difficult, because symptoms can vary so much from person to person. In addition, it can be very difficult to determine exactly what type of neuropathy a patient has. A physician typically will compile a thorough medical history and perform a complete physical examination of the patient. In addition, a neurological examination is often performed.

Various tests may be performed to pinpoint the cause of a patient’s peripheral neuropathy. For example, blood tests may reveal the presence of diabetes, liver or kidney dysfunction, or vitamin deficiencies. A spinal tap may be used to look for abnormal antibodies in a patient’s cerebrospinal fluid that my indicate neuropathy. Imaging tests such as computed axial tomography (CAT scan) and magnetic resonance imaging (MRI) also may be helpful.

Other tests that may be performed include:

• Nerve conduction velocity (NCV) tests. A nerve fiber is stimulated, which generates an electrical impulse. An electrode further down the nerve’s pathway records the speed of impulse transmission. Abnormal results may indicate nerve damage.
  
  
• Electromyography (EMG). A needle is inserted into a muscle to compare electrical activity in muscles at rest and during muscle contraction.
  
  
• Nerve biopsy. Removes a sample of nerve tissue for analysis, most often from the lower leg.
  
  
• Skin biopsy. Thin skin sample is obtained to examine the endings of nerve fibers.