The quantitative sudomotor axon reflex test (QSART) is a measurement of the nerves that control your sweating. The QSART may help determine if you have a disorder of the autonomic nervous system, which controls the workings of your internal organs.
The quantitative sudomotor axon reflex test (QSART, or sweat test) measures the nerves that control sweating. The test can help diagnose autonomic nervous system disorders, peripheral neuropathies and some types of pain disorders. The autonomic nervous system controls the working of your body’s internal organs, which includes regulating body temperature, blood pressure, heart rate and digestion.
The test involves a mild electrical stimulation on the skin called iontophoresis, which allows acetylcholine, a naturally occurring chemical, to stimulate your sweat glands. The QSART measures the volume of sweat produced by this stimulation.
You can eat a light meal. However:
Some medications can interfere with the test. Make sure your provider knows all the medications you’re taking.
Please come to the test room wearing loose clothing. You’ll be asked to remove your shoes and socks, including compression stockings. The technician will discuss the steps of the test and answer any questions you may have. Then:
The test takes approximately 45 minutes to one hour. A mild burning discomfort may be experienced at the site of stimulation during the test.
Your data is collected by the technician, and the final report is sent to the provider who referred you for the test. Within a few days your provider will provide you with the results. Different clinics may have different procedures. Ask your provider for details on your test results and follow-up.
Last reviewed by a Cleveland Clinic medical professional on 12/06/2016.
Learn more about our editorial process.