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Quantitative Sudomotor Axon Reflex Test (QSART)
*This test requires advanced equipment and specific training for scoring. For Training please email Dr. Phillip A. Low
The Patent for this test is held by: WR Medical Electronics Co.
Supplemental: Neuromuscular Diseases (NMD) and Parkinson's Disease (PD)
Short Description of Instrument

The Quantitative Sudomotor Axon Reflex Test (QSART) depends on the integrity of postganglionic sympathetic sudomotor axons and sweat glands. The stimulus for the QSART is iontrophoretically applied acetylcholine.
Recordings are typically performed from multiple sites, such as the medial forearm, proximal leg, distal leg and dorsum of the foot.


The latency, duration, amplitude of the response are recorded.

Clinicians should be cautious when using thermoregulatory testing to differentiate PD from other neurodegenerative disorders, such as multiple systems atrophy. In early PD, thermoregulatory dysfunction is mostly consistent with central and pre-ganglionic autonomic dysfunction. As PD progresses, an increasing percentage of patient will also show evidence of post-ganglionic sympathetic abnormalities. Tests of sudomotor function are often abnormal in PD, especially in advanced stages.
The QSART has been found to be sensitive and reproducible.
Low PA. Laboratory evaluation of autonomic dysfunction, In: Low PA, ed. Clinical autonomic disorders: evaluation and management. 2nd ed.
Philadelphia: Lippincott-Raven, 1997: 179-208.
Low PA,. Composite autonomic scores scale for laboratory quantification of generalized autonomic failure. Mayo Clin Proc 1993; 68: 748-752.
Cohen J, Low P, Fealey R, et al. Somatic and autonomic function in progressive autonomic failure and multiple systems atrophy. Ann Neurol 1987; 22: 692-699.
Low PA, Caskey PE, Tuck RR, Fealey RD, Dyck PJ. Quantitative sudomotor axon reflex test in normal and neuropathic subjects. Ann Neurol. 1983;14(5):573-580.


Document last updated June 2018