Definition
The Quantitative Sudomotor Axon Reflex Test (QSART) measures how well the nerves that control sweating are working.
Reasons for Procedure
QSART may be done to diagnose or assess:
- Problems with the part of the nervous system that controls things such as breathing
- Peripheral neuropathies
- Pain disorders, such as complex regional pain syndrome
What to Expect
Prior to Test
- Do not eat or drink anything with caffeine or smoke 4 hours before the test.
- Do not drink anything with alcohol for 12 to 14 hours before the test.
- Talk to your doctor if you take any medicines, herbs, or supplements.
Certain medicines may interfere with the test. These medicines may need to be stopped up to 1 week before the procedure. Talk to your doctor before the procedure about all medicines you are taking.
Anesthesia
Anesthesia will not be needed. The test does not cause pain, just a mild burning or discomfort.
Description of the Procedure
The skin on the leg and wrist will be cleaned. Three electrodes filled with a chemical will be placed on the leg and 1 electrode will be placed on the wrist. A mild electrical current will be used to help the chemical stimulate the sweat glands. The sweat response is measured.
How Long Will It Take?
2 to 3 hours
Will It Hurt?
A mild burning sensation may be felt at the electrode during the test.
Post-procedure Care
At the Care Center
Right after the procedure, the electrodes will be removed and your skin will be cleaned. You can leave after the procedure.
It may take a few days to receive the test results.
Problems To Look Out For
Call your doctor if you have a rash at the electrode site.
If you think you have an emergency, call for medical help right away.
RESOURCES
UPMC Department of Neurology https://upmc.com/services/neurology
The Foundation for Peripheral Neuropathy https://www.foundationforpn.org
CANADIAN RESOURCES
Health Canada http://canada.ca
The Hereditary Neuropathy Foundation of Canada http://hnfcanada.com
References
Autonomic disorders program. Stanford Health Care website. Available at: https://stanfordhealthcare.org/medical-clinics/autonomic-disorders-program/autonomic-testing-laboratory.html. Accessed April 14, 2022.
Automatic neuropathy. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/autonomic-neuropathy. Accessed April 14, 2022.
Diagnosing nerve disorders. Oregon Health and Science University Brain Institute website. Available at: http://www.ohsu.edu/brain-institute/diagnosing-nerve-disorders. Accessed April 14, 2022.
Peripheral neuropathy fact sheet. National Institute of Neurological Disorders and Stroke website. Available at: https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Peripheral-Neuropathy-Fact-Sheet. Accessed April 14, 2022
Quantitative sudomotor axon reflex test (QSART). Cleveland Clinic website. Available at: https://my.clevelandclinic.org/health/articles/qsart. Accessed April 14, 2022.
Revision Information
- Reviewer: EBSCO Medical Review Board Dr. Lukas Rimas, MD
- Review Date: 03/2022
- Update Date: 04/14/2022