Quantitative Sensory Testing

POLICY NUMBER

A.2.01.39

DESCRIPTION

Quantitative sensory testing (QST) systems are used for the noninvasive assessment and quantification of sensory nerve function in individuals with symptoms of, or the potential for, neurologic damage or disease. Types of sensory testing include current perception threshold testing, pressure-specified sensory testing, vibration perception testing (VPT), and thermal sensory testing. Information on sensory deficits identified using QST has been used in research settings to better understand neuropathic pain. It could be used to diagnose conditions linked to nerve damage and disease, and to improve patient outcomes by impacting management strategies.

Nerve Damage and Disease

Nerve damage and nerve diseases can reduce functional capacity and lead to neuropathic pain. There are also racial and ethnic disparities due to biological factors as well as social and environmental contributors in diseases that can lead to neuropathic pain. For example, incidence of neuropathy due to diabetic microvascular complications is higher in minority populations compared to non-Hispanic Whites.

TreatmentThere is a need for tests that can objectively measure sensory thresholds. Moreover, quantitative sensory testing (QST) could aid in the early diagnosis of disease. Also, although the criterion standard for evaluation of myelinated, large fibers is the electromyography nerve conduction study, there are no criterion standard reference tests to diagnose small fiber dysfunction.

Quantitative Sensory TestingQuantitative sensory test (QST) systems measure and quantify the amount of physical stimuli required for sensory perception to occur. As sensory deficits increase, the perception threshold of QST will increase, which may be informative in documenting the progression of neurologic damage or disease. Currently, QST has not been established for use as a sole tool for diagnosis and management but has been used with standard evaluative and management procedures (e.g., physical and neurologic examination, monofilament testing, pinprick, grip and pinch strength, Tinel sign,and Phalen and Roos test) to enhance the diagnosis and treatment-planning process, and to confirm physical findings with quantifiable data. Stimuli used in QST includes touch, pressure, pain, thermal (warm and cold), or vibratory stimuli.

Thecriterion standard for evaluation of myelinated, large fibers is the electromyography nerve conduction study. However, the function of smaller myelinated and unmyelinated sensory nerves, which may show pathologic changes before the involvement of the motor nerves, cannot be detected by nerve conduction studies. Small fiber neuropathy has traditionally been a diagnosis of exclusion in patients who have symptoms of distal neuropathy and a negative nerve conduction study.

Depending on the type of stimuli used, QST can assess both small and large fiber dysfunction. Touch and vibration measure the function of large myelinated A-alpha and A-beta sensory fibers. Thermal stimulation devices are used to evaluate pathology of small myelinated and unmyelinated nerve fibers; they can be used to assess heat and cold sensation, as well as thermal pain thresholds. Pressure-specified sensory devices assess large myelinated sensory nerve function by quantifying the thresholds of pressure detected with light, static, and moving touch. Finally, current perception threshold testing involves the quantification of the sensory threshold to transcutaneous electrical stimulation. In current perception threshold testing, typically 3 frequencies are tested: 5 Hz, designed to assess C fibers; 250 Hz, designed to assess A-delta fibers; and 2,000 Hz, designed to assess A-beta fibers. Results are compared with those of a reference population.

Because QST combines the objective physical, sensory stimuli with the subject patient response, it is psychophysical and requires patients who are alert, able to follow directions, and cooperative. Also, to get reliable results, examinations need to include standardized instructions to the patients, and stimuli must be applied consistently by trained staff.Psychophysical tests have greater inherent variability, making their results more difficult to reproduce.

Primarily, QST has been applied in patients with conditions associated with nerve damage and neuropathic pain. A retrospective analysis of a prospective database maintained by the German Research Network on Neuropathic Pain by Forstenpointner and colleagues (2021) compared QST profiles between patients with painful neuropathic conditions (n=332), patients with neuropathic conditions who did not report pain (n=111), and healthy controls (n=112). After extensive QST testing, including thermal, mechanical/vibration, and pain sensitivity, the researchers found similar QST profiles between patients who reported pain and patients who did not report pain, which raises concern about the role of QST in general in decision-making for neuropathic conditions. There have also been preliminary investigations to identify sensory deficits associated with conditions such as autism spectrum disorder, Tourette syndrome, restless legs syndrome, musculoskeletal pain, and response to opioid treatment.

A number of quantitative sensory testing (QST) devices have been cleared for marketing by the U.S. Food and Drug Administration (FDA) through the 510(k) process. Examples are listed below.

FDA-Approved Quantitative Sensory Testing Devices

POLICY

Quantitative sensory testing, including but not limited to current perception threshold testing, pressure-specified sensory device testing, vibration perception threshold testing, and thermal threshold testing, is considered investigational.

POLICY EXCEPTIONS

Federal Employee Program (FEP) may dictate that all devices approved by the FDA may not be considered investigational and thus, these devices may be assessed only on the basis of their medical necessity.

POLICY GUIDELINES

The coverage guidelines outlined in the Medical Policy Manual should not be used in lieu of the Member's specific benefit plan language.

Investigative is defined as the use of any treatment procedure, facility, equipment, drug, device, or supply not yet recognized as a generally accepted standard of good medical practice for the treatment of the condition being treated and; therefore, is not considered medically necessary. For the definition of Investigative, “generally accepted standards of medical practice” means standards that are based on credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, and physician specialty society recommendations, and the views of medical practitioners practicing in relevant clinical areas and any other relevant factors. In order for equipment, devices, drugs or supplies [i.e, technologies], to be considered not investigative, the technology must have final approval from the appropriate governmental bodies, and scientific evidence must permit conclusions concerning the effect of the technology on health outcomes, and the technology must improve the net health outcome, and the technology must be as beneficial as any established alternative and the improvement must be attainable outside the testing/investigational setting. 

POLICY HISTORY

8/2001: Approved by Medical Policy Advisory Committee (MPAC).

2/12/2002: Investigational definition added.

4/18/2002: Type of Service and Place of Service deleted.

8/5/2002: Code Reference section revised.

3/7/2003: Code Reference section updated.

10/14/2004: Code Reference section reviewed, no changes.

1/4/2007: Policy updated to include quantitative sensory testing (QST) and pressure-specified sensory testing as investigational. CPT codes 0106T, 0107T, 0108T, 0109T, and 0110T added to the non-covered codes.

4/29/2008: Policy reviewed, no changes.

04/14/2010: Policy Exception section revised to include FEP language, Source(s) section revised to remove outdated material; Policy Statement unchanged.

10/21/2010: Policy review; no changes.

10/05/2011: Policy description updated. Added vibration perception threshold testing and thermal threshold testing as investigational.

11/28/2012: Policy reviewed; no changes.

12/13/2013: Policy reviewed; no changes.

11/17/2014: Policy reviewed; description updated. Policy statement unchanged.

07/27/2015: Code Reference section updated for ICD-10.

12/21/2015: Policy description updated regarding devices. Policy statement unchanged. Investigative definition updated in policy guidelines section.

06/01/2016: Policy number A.2.01.39 added.

07/11/2017: Policy description updated regarding devices. Policy statement unchanged.

06/27/2018: Policy description updated regarding nerve damage and diseases. Policy statement unchanged.

07/05/2019: Policy reviewed; no changes.

11/17/2020: Policy reviewed; no changes.

08/25/2021: Policy description updated regarding a retrospective analysis comparing QST profiles between patients. Policy statement unchanged.

07/12/2022: Policy description updated regarding neuropathic pain and devices. Policy statement unchanged.

07/18/2023: Policy reviewed; no changes.

07/09/2024: Policy reviewed; no changes.

08/18/2025: Policy description updated. Policy statement unchanged.

SOURCE(S)

Blue Cross Blue Shield Association policy # 2.01.39

CODE REFERENCE

This may not be a comprehensive list of procedure codes applicable to this policy.

Investigational Codes

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