The goals of testing are:
- To diagnose the presence of neuropathy and distinguish it from other conditions that may cause similar symptoms
- Identify the cause, where possible
- Identify underlying conditions that make it worse
- Detect and evaluate complications
- Evaluate the location, extent, and severity of the nerve damage and assess organ function
Laboratory testing is used to look for underlying conditions that may cause or contribute to a neuropathy, detect complications, and evaluate organ function. Testing may include:
- Glucose – to detect diabetes and evaluate glucose control
- Comprehensive Metabolic Panel (CMP) – to evaluate liver, kidney, and other organ function; to detect metabolic problems
- Vitamin B12 – and other vitamin tests as indicated to detect vitamin deficiencies
- Thyroid Panel – to detect hypothyroidism
- CSF Analysis – to detect abnormalities or infections in the central nervous system
- Specific tests for autoimmune disorders
- Specific tests for infectious conditions, such as shingles (varicella zoster virus), Lyme disease, HIV/AIDS, cytomegalovirus (CMV), Epstein-Barr virus, and syphilis
- Heavy metal tests – to detect poisoning
- Tests for medications such as phenytoin, long-term use of which can cause peripheral neuropathy
- CBC (Complete Blood Count) – to detect blood cell abnormalities, infection, and metabolic problems
- Rarely, genetic testing to identify certain inherited disorders
Some labs offer a panel of antibody tests, such as a motor neuropathy antibody panel and a sensory neuropathy antibody panel, to aid in diagnosis. Elevations in certain antibodies have been associated with various neuropathies.
Testing typically begins with a neurological evaluation and clinical history and may include:
- Nerve conduction tests – to evaluate nerve transmission
- Electromyography (EMG) – to measure muscle activity
- Nerve biopsy – to evaluate nerve damage
- Skin biopsy – to evaluate nerve endings
Imaging scans to evaluate internal organs, bones, and blood vessels and to detect tumors may include:
- Computed tomography (CT scan)
- Magnetic Resonance Imaging (MRI)
See Radiologyinfo.org for more on these.
Examinations of affected body parts, such as the feet, are conducted to assess their condition and the degree of sensation loss.
If autonomic nerve involvement is suspected, additional testing may be performed to evaluate heart rate, blood pressure, the digestive tract, pupil response, and sweating.