Diagnosis of neuropathy is based on medical history, symptoms and a physical examination. Additional tests may be done to determine the type or extent of damage to the nerves.

When obtaining a medical history, the physician will consider the following factors:

• Length of time with diabetes
• Time since initial awareness of symptoms
• Glucose (blood sugar) levels
• Smoking and alcohol use
• Family history of diabetes
• Blood pressure
• Levels of cholesterol

In reviewing symptoms, the physician will focus on:

• Description of the symptoms
• Change of symptoms over time
• Location of the problems
• Description of the type of discomfort, such as pain, numbness or tingling sensations
• Weakness in feet, legs, arms or hands
• Dizziness or fainting
• Nausea or vomiting
• Problems with urination or bowel movements
• Sexual response and function
• Problems with vision or hearing
• Speech or swallowing difficulties
• Problems with temperature or perspiration
• Exercise patterns
• Any other contributing factors

After review of the medical history and symptoms, the physician will conduct a physical examination. An evaluation of the feet will be included to assess feeling and circulation. A neurological examination may be be performed to evaluate muscle control, sensation and reflexes. Muscle strength, balance and coordination can also be measured using standardized tests.

Several diagnostic tests may be administered to determine the extent of nerve or muscle damage due to the neuropathy, including:

• Nerve conduction velocity (NCV). Small electrodes are placed on the arms and legs and a low-power electric current is sent along the nerve. These pulses create a tingling sensation and usually are not painful. The physician checks for a slow or weak transmission of the current which indicates damage to that nerve.
  
  
• Electromyography (EMG). Small, thin needles are inserted into muscles and the responses are recorded on an EMG machine. Although there may be some pain when the needle is inserted, it usually becomes less painful as the test is conducted. No electrical shocks or injections are given through the needle. The needles measure slower or weaker responses indicating muscle damage as the result of neuropathy.
  
  
• Quantitative sensory testing (QST). In this test, various hot, cold and vibrating stimulations are placed on the body to measure sensation. The individual indicates when any sensation is felt as a result of the stimulation. There are no electrical shocks or needles in this test. The responses are used to evaluate the function of the small and large nerve endings, which may be damaged from neuropathy.

Other tests that may be used in the diagnosis and management of diabetic neuropathy include:

• Ultrasound. This test uses high-frequency sound waves to obtain images of the body. It allows physicians to view internal organs, such as the kidneys and bladder, and their functions. An ultrasound can be used to view the bladder and urinary tract for problems associated with autonomic neuropathy.
  
  
• Gastric emptying study. This test uses a small amount of radioactive material (tracer) to allow physicians to track food as it progresses through the gastrointestinal tract. Several hours after the patient eats a meal containing the tracer, a scanner is placed over the stomach that measures the amount of radioactivity in the stomach. This test may help to diagnose digestive problems common with autonomic neuropathy, such as gastroparesis.
  
  
• Nerve biopsy or skin biopsy. A minor surgical procedure is performed to obtain a sample for diagnosis of various disorders. It is used to evaluate a sample of nerve or skin tissue. A skin biopsy is common, but a nerve biopsy is more complicated and used only in certain circumstances such as research settings. A biopsy may help physicians identify nerve degeneration and confirm specific conditions found in neuropathy.

Based on the diagnostic tests, a physician may refer the patient to specialists for further tests and treatment. These specialists include:

• Neurologist (for nervous system disorders)
• Gastroenterologist (for digestive disorders)
• Urologist (for genitourinary tract disorders)
• Orthopedist (for skeletal and muscle disorders)
• Podiatrist (for foot care)
• Ophthalmologist(for eye care)
• Audiologist (for hearing)

Once neuropathy has been diagnosed, it is important for the patient to receive extended care and medical treatment. With close monitoring, the patient may be able to reduce the symptoms or neuropathy and avoid further complications.