Peripheral neuropathy has many potential causes. Besides a physical exam, which may include blood tests, diagnosis usually requires:
- A full medical history. Your doctor will review your medical history, including your symptoms, your lifestyle, exposure to toxins, drinking habits and a family history of nervous system (neurological) diseases.
- Neurological examination. Your doctor might check your tendon reflexes, your muscle strength and tone, your ability to feel certain sensations, and your posture and coordination.
Your doctor may order tests, including:
- Blood tests. These can detect vitamin deficiencies, diabetes, abnormal immune function and other indications of conditions that can cause peripheral neuropathy.
- Imaging tests. CT or MRI scans can look for herniated disks, tumors or other abnormalities.
- Nerve function tests. Electromyography records electrical activity in your muscles to detect nerve damage. A probe sends electrical signals to a nerve, and an electrode placed along the nerve's pathway records the nerve's response to the signals (nerve conduction studies).
- Other nerve function tests. These might include an autonomic reflex screen that records how the autonomic nerve fibers work, a sweat test, and sensory tests that record how you feel touch, vibration, cooling and heat.
- Nerve biopsy. This involves removing a small portion of a nerve, usually a sensory nerve, to look for abnormalities.
- Skin biopsy. Your doctor removes a small portion of skin to look for a reduction in nerve endings.