Quantitative sensory testing (QST) is an examination used to help detect damage to small and large nerve endings in the body. A number of disorders that cause nerve damage (neuropathies) may be diagnosed with QST, such as:

• Peripheral neuropathy. Damage to the peripheral nerves, often those that serve the legs.
  
  
• Proximal neuropathy. Nerve damage that primarily affects the hips, thighs and buttocks.
  
  
• Carpal tunnel syndrome. A condition that affects the median nerve of the wrist.
  
  

  

• Demyelinating diseases. Disorders that involve a loss of myelin, the sheath composed of white matter that protects and insulates nerve endings. An example is multiple sclerosis.
  
  
• Radiculopathy. A form of focal neuropathy characterized by irritated nerves, such as pinched nerves in the back or neck.
  
  
• Complex regional pain syndrome. A condition in which the nerves are abnormally sensitive.

In addition to diagnosing different types of neuropathy, QST may be used to monitor the state of a patient’s previously diagnosed neuropathy in order to determine the patient’s response to treatment.

QST consists of delivering a series of hot, cold and vibrating impulses to affected and unaffected regions of the body. The impulses are administered at specific intensity levels to test a patient’s sensory threshold (the minimum and maximum point at which an individual can feel the stimulus). A physician conducts the assessment using standardized sensory testing instruments.

QST generally takes place in a physician’s office. It is a noninvasive procedure, meaning that it does not involve inserting needles or electric probes into the body. QST requires no special pretesting preparations by the patient, and side effects after testing do not normally occur.